diff --git a/lib/ogc/gml.rb b/lib/ogc/gml.rb
index cda57de..fe0b2be 100644
--- a/lib/ogc/gml.rb
+++ b/lib/ogc/gml.rb
@@ -1,18 +1,22 @@
 # frozen_string_literal: true
 
+require "lutaml/model"
+
+Lutaml::Model::Config.configure do |config|
+  require "lutaml/model/xml_adapter/nokogiri_adapter"
+  config.xml_adapter = Lutaml::Model::XmlAdapter::NokogiriAdapter
+end
+
 require_relative "gml/version"
 
 module Ogc
   module Gml
     class Error < StandardError; end
+
     # Your code goes here...
   end
 end
 
-require 'shale'
-require 'shale/adapter/nokogiri'
-Shale.xml_adapter = Shale::Adapter::Nokogiri
-
 require_relative "gml/abstract_continuous_coverage"
 require_relative "gml/abstract_coordinate_operation"
 require_relative "gml/abstract_coordinate_system"
diff --git a/lib/ogc/gml/abstract_continuous_coverage.rb b/lib/ogc/gml/abstract_continuous_coverage.rb
index 8e06801..391d840 100644
--- a/lib/ogc/gml/abstract_continuous_coverage.rb
+++ b/lib/ogc/gml/abstract_continuous_coverage.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "coverage_function"
 require_relative "abstract_coverage"
 
diff --git a/lib/ogc/gml/abstract_coordinate_operation.rb b/lib/ogc/gml/abstract_coordinate_operation.rb
index fd240a7..e8d74cc 100644
--- a/lib/ogc/gml/abstract_coordinate_operation.rb
+++ b/lib/ogc/gml/abstract_coordinate_operation.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "coordinate_operation_accuracy"
 require_relative "crs_property"
@@ -9,10 +9,10 @@
 module Ogc
   module Gml
     class AbstractCoordinateOperation < AbstractTopology
-      attribute :remarks, Shale::Type::String
-      attribute :domain_of_validity, Shale::Type::String
-      attribute :scope, Shale::Type::String, collection: true
-      attribute :operation_version, Shale::Type::String
+      attribute :remarks, :string
+      attribute :domain_of_validity, :string
+      attribute :scope, :string, collection: true
+      attribute :operation_version, :string
       attribute :coordinate_operation_accuracy, CoordinateOperationAccuracy, collection: true
       attribute :source_crs, CRSProperty
       attribute :target_crs, CRSProperty
diff --git a/lib/ogc/gml/abstract_coordinate_system.rb b/lib/ogc/gml/abstract_coordinate_system.rb
index 58cdea4..a087566 100644
--- a/lib/ogc/gml/abstract_coordinate_system.rb
+++ b/lib/ogc/gml/abstract_coordinate_system.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -10,15 +10,15 @@
 
 module Ogc
   module Gml
-    class AbstractCoordinateSystem < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :aggregation_type, Shale::Type::String
+    class AbstractCoordinateSystem < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :aggregation_type, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
       attribute :axis, CoordinateSystemAxisProperty, collection: true
 
       xml do
diff --git a/lib/ogc/gml/abstract_coverage.rb b/lib/ogc/gml/abstract_coverage.rb
index ec9e68b..c460a80 100644
--- a/lib/ogc/gml/abstract_coverage.rb
+++ b/lib/ogc/gml/abstract_coverage.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "bounding_shape"
 require_relative "domain_set"
 require_relative "location_property"
diff --git a/lib/ogc/gml/abstract_crs.rb b/lib/ogc/gml/abstract_crs.rb
index b25561c..041df71 100644
--- a/lib/ogc/gml/abstract_crs.rb
+++ b/lib/ogc/gml/abstract_crs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -11,9 +11,9 @@
 module Ogc
   module Gml
     class AbstractCRS < AbstractTopology
-      attribute :remarks, Shale::Type::String
-      attribute :domain_of_validity, Shale::Type::String, collection: true
-      attribute :scope, Shale::Type::String, collection: true
+      attribute :remarks, :string
+      attribute :domain_of_validity, :string, collection: true
+      attribute :scope, :string, collection: true
 
       xml do
         root "AbstractSingleCRS"
diff --git a/lib/ogc/gml/abstract_curve.rb b/lib/ogc/gml/abstract_curve.rb
index 454e1fd..9f787ac 100644
--- a/lib/ogc/gml/abstract_curve.rb
+++ b/lib/ogc/gml/abstract_curve.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_geometric_primitive"
 
 module Ogc
diff --git a/lib/ogc/gml/abstract_curve_segment.rb b/lib/ogc/gml/abstract_curve_segment.rb
index 940cf21..af1ed39 100644
--- a/lib/ogc/gml/abstract_curve_segment.rb
+++ b/lib/ogc/gml/abstract_curve_segment.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class AbstractCurveSegment < Shale::Mapper
-      attribute :num_derivatives_at_start, Shale::Type::Integer#, default: -> { "0" }
-      attribute :num_derivatives_at_end, Shale::Type::Integer#, default: -> { "0" }
-      attribute :num_derivative_interior, Shale::Type::Integer#, default: -> { "0" }
+    class AbstractCurveSegment < Lutaml::Model::Serializable
+      attribute :num_derivatives_at_start, :integer #, default: -> { "0" }
+      attribute :num_derivatives_at_end, :integer #, default: -> { "0" }
+      attribute :num_derivative_interior, :integer #, default: -> { "0" }
 
       xml do
         root "AbstractCurveSegment"
diff --git a/lib/ogc/gml/abstract_datum.rb b/lib/ogc/gml/abstract_datum.rb
index e8f9524..7b50a64 100644
--- a/lib/ogc/gml/abstract_datum.rb
+++ b/lib/ogc/gml/abstract_datum.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -11,11 +11,11 @@
 module Ogc
   module Gml
     class AbstractDatum < AbstractTopology
-      attribute :remarks, Shale::Type::String
-      attribute :domain_of_validity, Shale::Type::String
-      attribute :scope, Shale::Type::String, collection: true
+      attribute :remarks, :string
+      attribute :domain_of_validity, :string
+      attribute :scope, :string, collection: true
       attribute :anchor_definition, Code
-      attribute :realization_epoch, Shale::Type::Date
+      attribute :realization_epoch, :date
 
       xml do
         root "AbstractDatum"
diff --git a/lib/ogc/gml/abstract_feature.rb b/lib/ogc/gml/abstract_feature.rb
index 4eeb67e..959a2b7 100644
--- a/lib/ogc/gml/abstract_feature.rb
+++ b/lib/ogc/gml/abstract_feature.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "bounding_shape"
 require_relative "code"
diff --git a/lib/ogc/gml/abstract_feature_collection.rb b/lib/ogc/gml/abstract_feature_collection.rb
index e0013b4..48eb605 100644
--- a/lib/ogc/gml/abstract_feature_collection.rb
+++ b/lib/ogc/gml/abstract_feature_collection.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "bounding_shape"
 require_relative "feature_array_property"
 require_relative "feature_property"
diff --git a/lib/ogc/gml/abstract_general_conversion.rb b/lib/ogc/gml/abstract_general_conversion.rb
index 96ee48b..d27d063 100644
--- a/lib/ogc/gml/abstract_general_conversion.rb
+++ b/lib/ogc/gml/abstract_general_conversion.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -12,9 +12,9 @@
 module Ogc
   module Gml
     class AbstractGeneralConversion < AbstractTopology
-      attribute :remarks, Shale::Type::String
-      attribute :domain_of_validity, Shale::Type::String
-      attribute :scope, Shale::Type::String, collection: true
+      attribute :remarks, :string
+      attribute :domain_of_validity, :string
+      attribute :scope, :string, collection: true
       attribute :coordinate_operation_accuracy, CoordinateOperationAccuracy, collection: true
 
       xml do
diff --git a/lib/ogc/gml/abstract_general_derived_crs.rb b/lib/ogc/gml/abstract_general_derived_crs.rb
index de771fa..4d34957 100644
--- a/lib/ogc/gml/abstract_general_derived_crs.rb
+++ b/lib/ogc/gml/abstract_general_derived_crs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "general_conversion_property"
 require_relative "abstract_crs"
 
diff --git a/lib/ogc/gml/abstract_general_operation_parameter.rb b/lib/ogc/gml/abstract_general_operation_parameter.rb
index 9106c22..78747db 100644
--- a/lib/ogc/gml/abstract_general_operation_parameter.rb
+++ b/lib/ogc/gml/abstract_general_operation_parameter.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_topology"
 
 module Ogc
   module Gml
     class AbstractGeneralOperationParameter < AbstractTopology
-      attribute :remarks, Shale::Type::String
-      attribute :minimum_occurs, Shale::Type::Integer
+      attribute :remarks, :string
+      attribute :minimum_occurs, :integer
 
       xml do
         root "AbstractGeneralOperationParameter"
diff --git a/lib/ogc/gml/abstract_general_operation_parameter_property.rb b/lib/ogc/gml/abstract_general_operation_parameter_property.rb
index cb4ece0..936fb38 100644
--- a/lib/ogc/gml/abstract_general_operation_parameter_property.rb
+++ b/lib/ogc/gml/abstract_general_operation_parameter_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_general_operation_parameter"
 
 module Ogc
   module Gml
-    class AbstractGeneralOperationParameterProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class AbstractGeneralOperationParameterProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_general_operation_parameter, AbstractGeneralOperationParameter
 
       xml do
diff --git a/lib/ogc/gml/abstract_general_parameter_value.rb b/lib/ogc/gml/abstract_general_parameter_value.rb
index 3e2744a..67fdb9a 100644
--- a/lib/ogc/gml/abstract_general_parameter_value.rb
+++ b/lib/ogc/gml/abstract_general_parameter_value.rb
@@ -1,10 +1,10 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class AbstractGeneralParameterValue < Shale::Mapper
+    class AbstractGeneralParameterValue < Lutaml::Model::Serializable
       xml do
         root "AbstractGeneralParameterValue"
         namespace "http://www.opengis.net/gml/3.2", "gml"
diff --git a/lib/ogc/gml/abstract_general_parameter_value_property.rb b/lib/ogc/gml/abstract_general_parameter_value_property.rb
index 4207cb6..eea82c5 100644
--- a/lib/ogc/gml/abstract_general_parameter_value_property.rb
+++ b/lib/ogc/gml/abstract_general_parameter_value_property.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_general_parameter_value"
 
 module Ogc
   module Gml
-    class AbstractGeneralParameterValueProperty < Shale::Mapper
+    class AbstractGeneralParameterValueProperty < Lutaml::Model::Serializable
       attribute :abstract_general_parameter_value, AbstractGeneralParameterValue
 
       xml do
diff --git a/lib/ogc/gml/abstract_general_transformation.rb b/lib/ogc/gml/abstract_general_transformation.rb
index 493de9e..2f48e51 100644
--- a/lib/ogc/gml/abstract_general_transformation.rb
+++ b/lib/ogc/gml/abstract_general_transformation.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_operation"
 
 module Ogc
diff --git a/lib/ogc/gml/abstract_geometric_aggregate.rb b/lib/ogc/gml/abstract_geometric_aggregate.rb
index 25f7e83..0fb0f38 100644
--- a/lib/ogc/gml/abstract_geometric_aggregate.rb
+++ b/lib/ogc/gml/abstract_geometric_aggregate.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_geometric_primitive"
 
 module Ogc
   module Gml
     class AbstractGeometricAggregate < AbstractGeometricPrimitive
-      attribute :aggregation_type, Shale::Type::String
+      attribute :aggregation_type, :string
 
       xml do
         root "AbstractGeometricAggregate"
diff --git a/lib/ogc/gml/abstract_geometric_primitive.rb b/lib/ogc/gml/abstract_geometric_primitive.rb
index 33370e9..06b87d6 100644
--- a/lib/ogc/gml/abstract_geometric_primitive.rb
+++ b/lib/ogc/gml/abstract_geometric_primitive.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -9,14 +9,14 @@
 
 module Ogc
   module Gml
-    class AbstractGeometricPrimitive < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :srs_name, Shale::Type::Value
-      attribute :srs_dimension, Shale::Type::Integer
-      attribute :axis_labels, Shale::Type::Value
-      attribute :uom_labels, Shale::Type::Value
+    class AbstractGeometricPrimitive < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :srs_name, :string
+      attribute :srs_dimension, :integer
+      attribute :axis_labels, :string
+      attribute :uom_labels, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/abstract_geometry.rb b/lib/ogc/gml/abstract_geometry.rb
index 1182fc0..80d444b 100644
--- a/lib/ogc/gml/abstract_geometry.rb
+++ b/lib/ogc/gml/abstract_geometry.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_geometric_primitive"
 
 module Ogc
diff --git a/lib/ogc/gml/abstract_gml.rb b/lib/ogc/gml/abstract_gml.rb
index 24ab79c..96d8cfe 100644
--- a/lib/ogc/gml/abstract_gml.rb
+++ b/lib/ogc/gml/abstract_gml.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
diff --git a/lib/ogc/gml/abstract_gridded_surface.rb b/lib/ogc/gml/abstract_gridded_surface.rb
index 17e1294..51c84b8 100644
--- a/lib/ogc/gml/abstract_gridded_surface.rb
+++ b/lib/ogc/gml/abstract_gridded_surface.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class AbstractGriddedSurface < Shale::Mapper
-      attribute :aggregation_type, Shale::Type::String
-      attribute :rows, Shale::Type::Integer
-      attribute :columns, Shale::Type::Integer
+    class AbstractGriddedSurface < Lutaml::Model::Serializable
+      attribute :aggregation_type, :string
+      attribute :rows, :integer
+      attribute :columns, :integer
 
       xml do
         root "AbstractGriddedSurface"
diff --git a/lib/ogc/gml/abstract_meta_data.rb b/lib/ogc/gml/abstract_meta_data.rb
index c80df29..7f5698e 100644
--- a/lib/ogc/gml/abstract_meta_data.rb
+++ b/lib/ogc/gml/abstract_meta_data.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class AbstractMetaData < Shale::Mapper
-      attribute :content, Shale::Type::String
-      attribute :id, Shale::Type::Value
+    class AbstractMetaData < Lutaml::Model::Serializable
+      attribute :content, :string
+      attribute :id, :string
 
       xml do
         root "AbstractMetaData"
diff --git a/lib/ogc/gml/abstract_parametric_curve_surface.rb b/lib/ogc/gml/abstract_parametric_curve_surface.rb
index 3f95c39..f516efc 100644
--- a/lib/ogc/gml/abstract_parametric_curve_surface.rb
+++ b/lib/ogc/gml/abstract_parametric_curve_surface.rb
@@ -1,11 +1,11 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class AbstractParametricCurveSurface < Shale::Mapper
-      attribute :aggregation_type, Shale::Type::String
+    class AbstractParametricCurveSurface < Lutaml::Model::Serializable
+      attribute :aggregation_type, :string
 
       xml do
         root "AbstractParametricCurveSurface"
diff --git a/lib/ogc/gml/abstract_ring.rb b/lib/ogc/gml/abstract_ring.rb
index da29833..f66b3b5 100644
--- a/lib/ogc/gml/abstract_ring.rb
+++ b/lib/ogc/gml/abstract_ring.rb
@@ -1,10 +1,10 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class AbstractRing < Shale::Mapper
+    class AbstractRing < Lutaml::Model::Serializable
       xml do
         root "AbstractRing"
         namespace "http://www.opengis.net/gml/3.2", "gml"
diff --git a/lib/ogc/gml/abstract_ring_property.rb b/lib/ogc/gml/abstract_ring_property.rb
index 644f6de..ae93bc4 100644
--- a/lib/ogc/gml/abstract_ring_property.rb
+++ b/lib/ogc/gml/abstract_ring_property.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_ring"
 
 module Ogc
   module Gml
-    class AbstractRingProperty < Shale::Mapper
+    class AbstractRingProperty < Lutaml::Model::Serializable
       attribute :abstract_ring, AbstractRing
 
       xml do
diff --git a/lib/ogc/gml/abstract_solid.rb b/lib/ogc/gml/abstract_solid.rb
index 089e8fe..7473842 100644
--- a/lib/ogc/gml/abstract_solid.rb
+++ b/lib/ogc/gml/abstract_solid.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_geometric_primitive"
 
 module Ogc
diff --git a/lib/ogc/gml/abstract_surface.rb b/lib/ogc/gml/abstract_surface.rb
index 27f5082..bc389bf 100644
--- a/lib/ogc/gml/abstract_surface.rb
+++ b/lib/ogc/gml/abstract_surface.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_geometric_primitive"
 
 module Ogc
diff --git a/lib/ogc/gml/abstract_surface_patch.rb b/lib/ogc/gml/abstract_surface_patch.rb
index 5daab12..fda3732 100644
--- a/lib/ogc/gml/abstract_surface_patch.rb
+++ b/lib/ogc/gml/abstract_surface_patch.rb
@@ -1,10 +1,10 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class AbstractSurfacePatch < Shale::Mapper
+    class AbstractSurfacePatch < Lutaml::Model::Serializable
       xml do
         root "AbstractSurfacePatch"
         namespace "http://www.opengis.net/gml/3.2", "gml"
diff --git a/lib/ogc/gml/abstract_time_complex.rb b/lib/ogc/gml/abstract_time_complex.rb
index 42d5f10..ef14b54 100644
--- a/lib/ogc/gml/abstract_time_complex.rb
+++ b/lib/ogc/gml/abstract_time_complex.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
diff --git a/lib/ogc/gml/abstract_time_geometric_primitive.rb b/lib/ogc/gml/abstract_time_geometric_primitive.rb
index b6b9039..a7d353a 100644
--- a/lib/ogc/gml/abstract_time_geometric_primitive.rb
+++ b/lib/ogc/gml/abstract_time_geometric_primitive.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -10,11 +10,11 @@
 
 module Ogc
   module Gml
-    class AbstractTimeGeometricPrimitive < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :frame, Shale::Type::Value, default: -> { "#ISO-8601" }
+    class AbstractTimeGeometricPrimitive < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :frame, :string, default: -> { "#ISO-8601" }
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/abstract_time_object.rb b/lib/ogc/gml/abstract_time_object.rb
index 09d4d31..d361b07 100644
--- a/lib/ogc/gml/abstract_time_object.rb
+++ b/lib/ogc/gml/abstract_time_object.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
diff --git a/lib/ogc/gml/abstract_time_primitive.rb b/lib/ogc/gml/abstract_time_primitive.rb
index 2dcb277..ae86ff1 100644
--- a/lib/ogc/gml/abstract_time_primitive.rb
+++ b/lib/ogc/gml/abstract_time_primitive.rb
@@ -1,11 +1,11 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 # require_relative "related_time"
 
 module Ogc
   module Gml
-    class RelatedTime < Shale::Mapper
+    class RelatedTime < Lutaml::Model::Serializable
     end
 
     class AbstractTimePrimitive < AbstractTopology
diff --git a/lib/ogc/gml/abstract_time_slice.rb b/lib/ogc/gml/abstract_time_slice.rb
index b5450f2..4c1839a 100644
--- a/lib/ogc/gml/abstract_time_slice.rb
+++ b/lib/ogc/gml/abstract_time_slice.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
diff --git a/lib/ogc/gml/abstract_time_topology_primitive.rb b/lib/ogc/gml/abstract_time_topology_primitive.rb
index 3db976d..bd21ed1 100644
--- a/lib/ogc/gml/abstract_time_topology_primitive.rb
+++ b/lib/ogc/gml/abstract_time_topology_primitive.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
diff --git a/lib/ogc/gml/abstract_topo_primitive.rb b/lib/ogc/gml/abstract_topo_primitive.rb
index 56b04d5..2499a86 100644
--- a/lib/ogc/gml/abstract_topo_primitive.rb
+++ b/lib/ogc/gml/abstract_topo_primitive.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
diff --git a/lib/ogc/gml/abstract_topology.rb b/lib/ogc/gml/abstract_topology.rb
index 9fc16c1..0717e26 100644
--- a/lib/ogc/gml/abstract_topology.rb
+++ b/lib/ogc/gml/abstract_topology.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "code"
 require_relative "code_with_authority"
 require_relative "meta_data_property"
@@ -8,10 +8,10 @@
 
 module Ogc
   module Gml
-    class AbstractTopology < Shale::Mapper
-      attribute :id, Shale::Type::Value
+    class AbstractTopology < Lutaml::Model::Serializable
+      attribute :id, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/affine_cs.rb b/lib/ogc/gml/affine_cs.rb
index e20caff..34015f8 100644
--- a/lib/ogc/gml/affine_cs.rb
+++ b/lib/ogc/gml/affine_cs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_system"
 
 module Ogc
diff --git a/lib/ogc/gml/affine_cs_property.rb b/lib/ogc/gml/affine_cs_property.rb
index 20fee1d..681004c 100644
--- a/lib/ogc/gml/affine_cs_property.rb
+++ b/lib/ogc/gml/affine_cs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "affine_cs"
 
 module Ogc
   module Gml
-    class AffineCSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class AffineCSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :affine_cs, AffineCS
 
       xml do
diff --git a/lib/ogc/gml/affine_placement.rb b/lib/ogc/gml/affine_placement.rb
index b1b7aac..3e743f0 100644
--- a/lib/ogc/gml/affine_placement.rb
+++ b/lib/ogc/gml/affine_placement.rb
@@ -1,17 +1,17 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "direct_position"
 require_relative "vector"
 
 module Ogc
   module Gml
-    class AffinePlacement < Shale::Mapper
+    class AffinePlacement < Lutaml::Model::Serializable
       attribute :location, DirectPosition
       attribute :ref_direction, Vector, collection: true
-      attribute :in_dimension, Shale::Type::Integer
-      attribute :out_dimension, Shale::Type::Integer
+      attribute :in_dimension, :integer
+      attribute :out_dimension, :integer
 
       xml do
         root "AffinePlacement"
diff --git a/lib/ogc/gml/angle.rb b/lib/ogc/gml/angle.rb
index 3910eb2..f7082ba 100644
--- a/lib/ogc/gml/angle.rb
+++ b/lib/ogc/gml/angle.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "measure"
 
 module Ogc
   module Gml
-    class Angle < Shale::Mapper
+    class Angle < Lutaml::Model::Serializable
       attribute :content, Measure
 
       xml do
diff --git a/lib/ogc/gml/arc.rb b/lib/ogc/gml/arc.rb
index d8b452a..31dfe6d 100644
--- a/lib/ogc/gml/arc.rb
+++ b/lib/ogc/gml/arc.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "arc_string"
 
 module Ogc
diff --git a/lib/ogc/gml/arc_by_bulge.rb b/lib/ogc/gml/arc_by_bulge.rb
index af5af8d..26ac11b 100644
--- a/lib/ogc/gml/arc_by_bulge.rb
+++ b/lib/ogc/gml/arc_by_bulge.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "vector"
 require_relative "arc"
 
 module Ogc
   module Gml
     class ArcByBulge < Arc
-      attribute :bulge, Shale::Type::Float
+      attribute :bulge, :float
       attribute :normal, Vector
 
       xml do
diff --git a/lib/ogc/gml/arc_by_center_point.rb b/lib/ogc/gml/arc_by_center_point.rb
index 80df0cc..aa951fc 100644
--- a/lib/ogc/gml/arc_by_center_point.rb
+++ b/lib/ogc/gml/arc_by_center_point.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "angle"
 require_relative "direct_position"
diff --git a/lib/ogc/gml/arc_string.rb b/lib/ogc/gml/arc_string.rb
index 442d165..ffd14c3 100644
--- a/lib/ogc/gml/arc_string.rb
+++ b/lib/ogc/gml/arc_string.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "coordinates"
 require_relative "direct_position_list"
@@ -11,8 +11,8 @@
 module Ogc
   module Gml
     class ArcString < AbstractCurveSegment
-      attribute :interpolation, Shale::Type::String
-      attribute :num_arc, Shale::Type::Integer
+      attribute :interpolation, :string
+      attribute :num_arc, :integer
       attribute :pos, DirectPosition, collection: true
       attribute :point_property, PointProperty, collection: true
       attribute :point_rep, PointProperty, collection: true
diff --git a/lib/ogc/gml/arc_string_by_bulge.rb b/lib/ogc/gml/arc_string_by_bulge.rb
index 3ce8a73..f84b93d 100644
--- a/lib/ogc/gml/arc_string_by_bulge.rb
+++ b/lib/ogc/gml/arc_string_by_bulge.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "vector"
 require_relative "arc_string"
 
 module Ogc
   module Gml
     class ArcStringByBulge < ArcString
-      attribute :bulge, Shale::Type::Float, collection: true
+      attribute :bulge, :float, collection: true
       attribute :normal, Vector, collection: true
 
       xml do
diff --git a/lib/ogc/gml/array.rb b/lib/ogc/gml/array.rb
index dc3e5f4..be0204e 100644
--- a/lib/ogc/gml/array.rb
+++ b/lib/ogc/gml/array.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "array_association"
 require_relative "code"
diff --git a/lib/ogc/gml/array_association.rb b/lib/ogc/gml/array_association.rb
index bf9eecf..57b2de0 100644
--- a/lib/ogc/gml/array_association.rb
+++ b/lib/ogc/gml/array_association.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class ArrayAssociation < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :abstract_object, Shale::Type::Value, collection: true
+    class ArrayAssociation < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :abstract_object, :string, collection: true
 
       xml do
         root "members"
diff --git a/lib/ogc/gml/association_role.rb b/lib/ogc/gml/association_role.rb
index 6c9912c..6f71444 100644
--- a/lib/ogc/gml/association_role.rb
+++ b/lib/ogc/gml/association_role.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class AssociationRole < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class AssociationRole < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
 
       xml do
         root "member"
diff --git a/lib/ogc/gml/b_spline.rb b/lib/ogc/gml/b_spline.rb
index 36f7595..4c8f22c 100644
--- a/lib/ogc/gml/b_spline.rb
+++ b/lib/ogc/gml/b_spline.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "bezier"
 
 module Ogc
diff --git a/lib/ogc/gml/bag.rb b/lib/ogc/gml/bag.rb
index 98d391c..ccdbaa5 100644
--- a/lib/ogc/gml/bag.rb
+++ b/lib/ogc/gml/bag.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "array_association"
 require_relative "association_role"
diff --git a/lib/ogc/gml/base_unit.rb b/lib/ogc/gml/base_unit.rb
index f18c63c..6cfa97f 100644
--- a/lib/ogc/gml/base_unit.rb
+++ b/lib/ogc/gml/base_unit.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -12,7 +12,7 @@
 module Ogc
   module Gml
     class BaseUnit < AbstractTopology
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
       attribute :quantity_type, StringOrRef
       attribute :quantity_type_reference, Reference
       attribute :catalog_symbol, Code
diff --git a/lib/ogc/gml/bezier.rb b/lib/ogc/gml/bezier.rb
index 6d9549c..f628ac5 100644
--- a/lib/ogc/gml/bezier.rb
+++ b/lib/ogc/gml/bezier.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "coordinates"
 require_relative "direct_position_list"
@@ -11,15 +11,15 @@
 module Ogc
   module Gml
     class Bezier < AbstractCurveSegment
-      attribute :interpolation, Shale::Type::String, default: -> { "polynomialSpline" }
-      attribute :is_polynomial, Shale::Type::Boolean
-      attribute :knot_type, Shale::Type::String
+      attribute :interpolation, :string, default: -> { "polynomialSpline" }
+      attribute :is_polynomial, :boolean
+      attribute :knot_type, :string
       attribute :pos, DirectPosition, collection: true
       attribute :point_property, PointProperty, collection: true
       attribute :point_rep, PointProperty, collection: true
       attribute :pos_list, DirectPositionList
       attribute :coordinates, Coordinates
-      attribute :degree, Shale::Type::Integer
+      attribute :degree, :integer
       attribute :knot, KnotProperty, collection: true
 
       xml do
diff --git a/lib/ogc/gml/boolean.rb b/lib/ogc/gml/boolean.rb
index 249f7a7..4571983 100644
--- a/lib/ogc/gml/boolean.rb
+++ b/lib/ogc/gml/boolean.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class Boolean < Shale::Mapper
-      attribute :content, Shale::Type::Boolean
-      attribute :nil_reason, Shale::Type::Value
+    class Boolean < Lutaml::Model::Serializable
+      attribute :content, :boolean
+      attribute :nil_reason, :string
 
       xml do
         root "Boolean"
diff --git a/lib/ogc/gml/bounding_shape.rb b/lib/ogc/gml/bounding_shape.rb
index 3a8320e..086401f 100644
--- a/lib/ogc/gml/bounding_shape.rb
+++ b/lib/ogc/gml/bounding_shape.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "envelope"
 
 module Ogc
   module Gml
-    class BoundingShape < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
+    class BoundingShape < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
       attribute :envelope, Envelope
-      attribute :null, Shale::Type::Value
+      attribute :null, :string
 
       xml do
         root "boundedBy"
diff --git a/lib/ogc/gml/cartesian_cs.rb b/lib/ogc/gml/cartesian_cs.rb
index 0ed7a80..a0f2e37 100644
--- a/lib/ogc/gml/cartesian_cs.rb
+++ b/lib/ogc/gml/cartesian_cs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_system"
 
 module Ogc
diff --git a/lib/ogc/gml/cartesian_cs_property.rb b/lib/ogc/gml/cartesian_cs_property.rb
index 7d6e7b4..364f447 100644
--- a/lib/ogc/gml/cartesian_cs_property.rb
+++ b/lib/ogc/gml/cartesian_cs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "cartesian_cs"
 
 module Ogc
   module Gml
-    class CartesianCSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class CartesianCSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :cartesian_cs, CartesianCS
 
       xml do
diff --git a/lib/ogc/gml/category.rb b/lib/ogc/gml/category.rb
index a85f561..05dfdb9 100644
--- a/lib/ogc/gml/category.rb
+++ b/lib/ogc/gml/category.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 
 module Ogc
   module Gml
-    class Category < Shale::Mapper
+    class Category < Lutaml::Model::Serializable
       attribute :content, Code
-      attribute :nil_reason, Shale::Type::Value
+      attribute :nil_reason, :string
 
       xml do
         root "Category"
diff --git a/lib/ogc/gml/category_extent.rb b/lib/ogc/gml/category_extent.rb
index efc9ffd..ee82e9a 100644
--- a/lib/ogc/gml/category_extent.rb
+++ b/lib/ogc/gml/category_extent.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code_or_nil_reason_list"
 
 module Ogc
   module Gml
-    class CategoryExtent < Shale::Mapper
+    class CategoryExtent < Lutaml::Model::Serializable
       attribute :content, CodeOrNilReasonList
 
       xml do
diff --git a/lib/ogc/gml/circle.rb b/lib/ogc/gml/circle.rb
index 67cec8e..cf7b5d1 100644
--- a/lib/ogc/gml/circle.rb
+++ b/lib/ogc/gml/circle.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "arc_string"
 
 module Ogc
diff --git a/lib/ogc/gml/circle_by_center_point.rb b/lib/ogc/gml/circle_by_center_point.rb
index 8500cfa..e5a1c29 100644
--- a/lib/ogc/gml/circle_by_center_point.rb
+++ b/lib/ogc/gml/circle_by_center_point.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "coordinates"
 require_relative "direct_position_list"
@@ -12,8 +12,8 @@
 module Ogc
   module Gml
     class CircleByCenterPoint < AbstractCurveSegment
-      attribute :interpolation, Shale::Type::String
-      attribute :num_arc, Shale::Type::Integer
+      attribute :interpolation, :string
+      attribute :num_arc, :integer
       attribute :pos, DirectPosition
       attribute :point_property, PointProperty
       attribute :point_rep, PointProperty
diff --git a/lib/ogc/gml/clothoid.rb b/lib/ogc/gml/clothoid.rb
index 85e54ef..1d3c402 100644
--- a/lib/ogc/gml/clothoid.rb
+++ b/lib/ogc/gml/clothoid.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "ref_location"
 require_relative "abstract_curve_segment"
@@ -8,11 +8,11 @@
 module Ogc
   module Gml
     class Clothoid < AbstractCurveSegment
-      attribute :interpolation, Shale::Type::String
+      attribute :interpolation, :string
       attribute :ref_location, RefLocation
-      attribute :scale_factor, Shale::Type::Float
-      attribute :start_parameter, Shale::Type::Float
-      attribute :end_parameter, Shale::Type::Float
+      attribute :scale_factor, :float
+      attribute :start_parameter, :float
+      attribute :end_parameter, :float
 
       xml do
         root "Clothoid"
diff --git a/lib/ogc/gml/code.rb b/lib/ogc/gml/code.rb
index abec306..0d4d540 100644
--- a/lib/ogc/gml/code.rb
+++ b/lib/ogc/gml/code.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class Code < Shale::Mapper
-      attribute :content, Shale::Type::String
-      attribute :code_space, Shale::Type::Value
+    class Code < Lutaml::Model::Serializable
+      attribute :content, :string
+      attribute :code_space, :string
 
       xml do
         root "LocationKeyWord"
diff --git a/lib/ogc/gml/code_or_nil_reason_list.rb b/lib/ogc/gml/code_or_nil_reason_list.rb
index a65a082..c828073 100644
--- a/lib/ogc/gml/code_or_nil_reason_list.rb
+++ b/lib/ogc/gml/code_or_nil_reason_list.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class CodeOrNilReasonList < Shale::Mapper
-      attribute :content, Shale::Type::Value
-      attribute :code_space, Shale::Type::Value
+    class CodeOrNilReasonList < Lutaml::Model::Serializable
+      attribute :content, :string
+      attribute :code_space, :string
 
       xml do
         root "CategoryList"
diff --git a/lib/ogc/gml/code_with_authority.rb b/lib/ogc/gml/code_with_authority.rb
index d0b9cb3..0237b91 100644
--- a/lib/ogc/gml/code_with_authority.rb
+++ b/lib/ogc/gml/code_with_authority.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 
 module Ogc
   module Gml
-    class CodeWithAuthority < Shale::Mapper
+    class CodeWithAuthority < Lutaml::Model::Serializable
       attribute :content, Code
-      attribute :code_space, Shale::Type::Value
+      attribute :code_space, :string
 
       xml do
         root "derivedCRSType"
diff --git a/lib/ogc/gml/composite_curve.rb b/lib/ogc/gml/composite_curve.rb
index f9f92a4..1d3a6ba 100644
--- a/lib/ogc/gml/composite_curve.rb
+++ b/lib/ogc/gml/composite_curve.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "curve_property"
 require_relative "abstract_geometric_aggregate"
 
diff --git a/lib/ogc/gml/composite_solid.rb b/lib/ogc/gml/composite_solid.rb
index 0aabbb1..e995ce4 100644
--- a/lib/ogc/gml/composite_solid.rb
+++ b/lib/ogc/gml/composite_solid.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "solid_property"
 require_relative "abstract_geometric_aggregate"
 
diff --git a/lib/ogc/gml/composite_surface.rb b/lib/ogc/gml/composite_surface.rb
index d3c5ef1..f1df75d 100644
--- a/lib/ogc/gml/composite_surface.rb
+++ b/lib/ogc/gml/composite_surface.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "surface_property"
 require_relative "abstract_geometric_aggregate"
 
diff --git a/lib/ogc/gml/composite_value.rb b/lib/ogc/gml/composite_value.rb
index 8d9e695..07869ba 100644
--- a/lib/ogc/gml/composite_value.rb
+++ b/lib/ogc/gml/composite_value.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -11,11 +11,11 @@
 
 module Ogc
   module Gml
-    class CompositeValue < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :aggregation_type, Shale::Type::String
+    class CompositeValue < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :aggregation_type, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/compound_crs.rb b/lib/ogc/gml/compound_crs.rb
index 6f518f5..2e08bcc 100644
--- a/lib/ogc/gml/compound_crs.rb
+++ b/lib/ogc/gml/compound_crs.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "single_crs_property"
 require_relative "abstract_crs"
 
 module Ogc
   module Gml
     class CompoundCRS < AbstractCRS
-      attribute :aggregation_type, Shale::Type::String
+      attribute :aggregation_type, :string
       attribute :component_reference_system, SingleCRSProperty, collection: true
 
       xml do
diff --git a/lib/ogc/gml/compound_crs_property.rb b/lib/ogc/gml/compound_crs_property.rb
index 0f92504..b1e113e 100644
--- a/lib/ogc/gml/compound_crs_property.rb
+++ b/lib/ogc/gml/compound_crs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "compound_crs"
 
 module Ogc
   module Gml
-    class CompoundCRSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class CompoundCRSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :compound_crs, CompoundCRS
 
       xml do
diff --git a/lib/ogc/gml/concatenated_operation.rb b/lib/ogc/gml/concatenated_operation.rb
index fbd310e..812dcf5 100644
--- a/lib/ogc/gml/concatenated_operation.rb
+++ b/lib/ogc/gml/concatenated_operation.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -12,10 +12,10 @@
 module Ogc
   module Gml
     class ConcatenatedOperation < AbstractCoordinateOperation
-      attribute :id, Shale::Type::Value
-      attribute :aggregation_type, Shale::Type::String
+      attribute :id, :string
+      attribute :aggregation_type, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/concatenated_operation_property.rb b/lib/ogc/gml/concatenated_operation_property.rb
index 741e640..52c9355 100644
--- a/lib/ogc/gml/concatenated_operation_property.rb
+++ b/lib/ogc/gml/concatenated_operation_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "concatenated_operation"
 
 module Ogc
   module Gml
-    class ConcatenatedOperationProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class ConcatenatedOperationProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :concatenated_operation, ConcatenatedOperation
 
       xml do
diff --git a/lib/ogc/gml/cone.rb b/lib/ogc/gml/cone.rb
index 9143544..b0800aa 100644
--- a/lib/ogc/gml/cone.rb
+++ b/lib/ogc/gml/cone.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "cylinder"
 
 module Ogc
diff --git a/lib/ogc/gml/control_point.rb b/lib/ogc/gml/control_point.rb
index a534b3d..799e8ec 100644
--- a/lib/ogc/gml/control_point.rb
+++ b/lib/ogc/gml/control_point.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "direct_position_list"
 require_relative "direct_position"
@@ -8,7 +8,7 @@
 
 module Ogc
   module Gml
-    class ControlPoint < Shale::Mapper
+    class ControlPoint < Lutaml::Model::Serializable
       attribute :pos_list, DirectPositionList
       attribute :pos, DirectPosition, collection: true
       attribute :point_property, PointProperty, collection: true
diff --git a/lib/ogc/gml/conventional_unit.rb b/lib/ogc/gml/conventional_unit.rb
index eb7c660..9d19d6e 100644
--- a/lib/ogc/gml/conventional_unit.rb
+++ b/lib/ogc/gml/conventional_unit.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -14,7 +14,7 @@
 module Ogc
   module Gml
     class ConventionalUnit < AbstractTopology
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
       attribute :quantity_type, StringOrRef
       attribute :quantity_type_reference, Reference
       attribute :catalog_symbol, Code
diff --git a/lib/ogc/gml/conversion.rb b/lib/ogc/gml/conversion.rb
index 562f421..d527ea7 100644
--- a/lib/ogc/gml/conversion.rb
+++ b/lib/ogc/gml/conversion.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_general_parameter_value_property"
 require_relative "operation_method_property"
 require_relative "abstract_general_conversion"
diff --git a/lib/ogc/gml/conversion_property.rb b/lib/ogc/gml/conversion_property.rb
index 24fba8c..01e451f 100644
--- a/lib/ogc/gml/conversion_property.rb
+++ b/lib/ogc/gml/conversion_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "conversion"
 
 module Ogc
   module Gml
-    class ConversionProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class ConversionProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :conversion, Conversion
 
       xml do
diff --git a/lib/ogc/gml/conversion_to_preferred_unit.rb b/lib/ogc/gml/conversion_to_preferred_unit.rb
index 1c609ef..b8b8ec4 100644
--- a/lib/ogc/gml/conversion_to_preferred_unit.rb
+++ b/lib/ogc/gml/conversion_to_preferred_unit.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "formula"
 
 module Ogc
   module Gml
-    class ConversionToPreferredUnit < Shale::Mapper
-      attribute :uom, Shale::Type::Value
-      attribute :factor, Shale::Type::Float
+    class ConversionToPreferredUnit < Lutaml::Model::Serializable
+      attribute :uom, :string
+      attribute :factor, :float
       attribute :formula, Formula
 
       xml do
diff --git a/lib/ogc/gml/coordinate_operation_accuracy.rb b/lib/ogc/gml/coordinate_operation_accuracy.rb
index 8877d47..c50b3f8 100644
--- a/lib/ogc/gml/coordinate_operation_accuracy.rb
+++ b/lib/ogc/gml/coordinate_operation_accuracy.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "string_or_ref"
 
 module Ogc
   module Gml
-    class CoordinateOperationAccuracy < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class CoordinateOperationAccuracy < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :reference_event, StringOrRef
 
       xml do
diff --git a/lib/ogc/gml/coordinate_operation_property.rb b/lib/ogc/gml/coordinate_operation_property.rb
index fb6fe37..ec96b06 100644
--- a/lib/ogc/gml/coordinate_operation_property.rb
+++ b/lib/ogc/gml/coordinate_operation_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_coordinate_operation"
 
 module Ogc
   module Gml
-    class CoordinateOperationProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class CoordinateOperationProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_coordinate_operation, AbstractCoordinateOperation
 
       xml do
diff --git a/lib/ogc/gml/coordinate_system_axis.rb b/lib/ogc/gml/coordinate_system_axis.rb
index c39323f..35e3695 100644
--- a/lib/ogc/gml/coordinate_system_axis.rb
+++ b/lib/ogc/gml/coordinate_system_axis.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -9,19 +9,19 @@
 
 module Ogc
   module Gml
-    class CoordinateSystemAxis < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :uom, Shale::Type::Value
+    class CoordinateSystemAxis < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :uom, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
       attribute :axis_abbrev, Code
       attribute :axis_direction, CodeWithAuthority
-      attribute :minimum_value, Shale::Type::Float
-      attribute :maximum_value, Shale::Type::Float
+      attribute :minimum_value, :float
+      attribute :maximum_value, :float
       attribute :range_meaning, CodeWithAuthority
 
       xml do
diff --git a/lib/ogc/gml/coordinate_system_axis_property.rb b/lib/ogc/gml/coordinate_system_axis_property.rb
index cf6d55d..a4327c7 100644
--- a/lib/ogc/gml/coordinate_system_axis_property.rb
+++ b/lib/ogc/gml/coordinate_system_axis_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "coordinate_system_axis"
 
 module Ogc
   module Gml
-    class CoordinateSystemAxisProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class CoordinateSystemAxisProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :coordinate_system_axis, CoordinateSystemAxis
 
       xml do
diff --git a/lib/ogc/gml/coordinate_system_property.rb b/lib/ogc/gml/coordinate_system_property.rb
index 555e611..a43eb04 100644
--- a/lib/ogc/gml/coordinate_system_property.rb
+++ b/lib/ogc/gml/coordinate_system_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_coordinate_system"
 
 module Ogc
   module Gml
-    class CoordinateSystemProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class CoordinateSystemProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_coordinate_system, AbstractCoordinateSystem
 
       xml do
diff --git a/lib/ogc/gml/coordinates.rb b/lib/ogc/gml/coordinates.rb
index 236c120..3abc0db 100644
--- a/lib/ogc/gml/coordinates.rb
+++ b/lib/ogc/gml/coordinates.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class Coordinates < Shale::Mapper
-      attribute :content, Shale::Type::String
-      attribute :decimal, Shale::Type::String, default: -> { "." }
-      attribute :cs, Shale::Type::String, default: -> { "," }
-      attribute :ts, Shale::Type::String, default: -> { " " }
+    class Coordinates < Lutaml::Model::Serializable
+      attribute :content, :string
+      attribute :decimal, :string, default: -> { "." }
+      attribute :cs, :string, default: -> { "," }
+      attribute :ts, :string, default: -> { " " }
 
       xml do
         root "coordinates"
diff --git a/lib/ogc/gml/count.rb b/lib/ogc/gml/count.rb
index bbe32e6..63f0f0f 100644
--- a/lib/ogc/gml/count.rb
+++ b/lib/ogc/gml/count.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class Count < Shale::Mapper
-      attribute :content, Shale::Type::Integer
-      attribute :nil_reason, Shale::Type::Value
+    class Count < Lutaml::Model::Serializable
+      attribute :content, :integer
+      attribute :nil_reason, :string
 
       xml do
         root "Count"
diff --git a/lib/ogc/gml/coverage_function.rb b/lib/ogc/gml/coverage_function.rb
index da785e1..4c4ada7 100644
--- a/lib/ogc/gml/coverage_function.rb
+++ b/lib/ogc/gml/coverage_function.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "grid_function"
 require_relative "mapping_rule"
@@ -8,7 +8,7 @@
 
 module Ogc
   module Gml
-    class CoverageFunction < Shale::Mapper
+    class CoverageFunction < Lutaml::Model::Serializable
       attribute :mapping_rule, StringOrRef
       attribute :coverage_mapping_rule, MappingRule
       attribute :grid_function, GridFunction
diff --git a/lib/ogc/gml/crs_property.rb b/lib/ogc/gml/crs_property.rb
index 64bf4de..29da859 100644
--- a/lib/ogc/gml/crs_property.rb
+++ b/lib/ogc/gml/crs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_crs"
 
 module Ogc
   module Gml
-    class CRSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class CRSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_crs, AbstractCRS
 
       xml do
diff --git a/lib/ogc/gml/cubic_spline.rb b/lib/ogc/gml/cubic_spline.rb
index f3fb829..d821953 100644
--- a/lib/ogc/gml/cubic_spline.rb
+++ b/lib/ogc/gml/cubic_spline.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "coordinates"
 require_relative "direct_position_list"
@@ -12,8 +12,8 @@
 module Ogc
   module Gml
     class CubicSpline < AbstractCurveSegment
-      attribute :interpolation, Shale::Type::String
-      attribute :degree, Shale::Type::Integer
+      attribute :interpolation, :string
+      attribute :degree, :integer
       attribute :pos, DirectPosition, collection: true
       attribute :point_property, PointProperty, collection: true
       attribute :point_rep, PointProperty, collection: true
diff --git a/lib/ogc/gml/curve.rb b/lib/ogc/gml/curve.rb
index 582bb5e..3573474 100644
--- a/lib/ogc/gml/curve.rb
+++ b/lib/ogc/gml/curve.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "curve_segment_array_property"
 require_relative "abstract_curve"
 
diff --git a/lib/ogc/gml/curve_array_property.rb b/lib/ogc/gml/curve_array_property.rb
index 613cdb8..0376cdd 100644
--- a/lib/ogc/gml/curve_array_property.rb
+++ b/lib/ogc/gml/curve_array_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_curve"
 require_relative "line_string"
 
 module Ogc
   module Gml
-    class CurveArrayProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class CurveArrayProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
       attribute :abstract_curve, AbstractCurve, collection: true
       attribute :curve, Curve, collection: true
       attribute :line_string, LineString, collection: true
diff --git a/lib/ogc/gml/curve_property.rb b/lib/ogc/gml/curve_property.rb
index b8375ef..d9d9a40 100644
--- a/lib/ogc/gml/curve_property.rb
+++ b/lib/ogc/gml/curve_property.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_curve"
 require_relative "curve"
@@ -9,10 +9,10 @@
 
 module Ogc
   module Gml
-    class CurveProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean
+    class CurveProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean
       attribute :abstract_curve, AbstractCurve
       attribute :curve, Curve
       attribute :orientable_curve, OrientableCurve
diff --git a/lib/ogc/gml/curve_segment_array_property.rb b/lib/ogc/gml/curve_segment_array_property.rb
index fba30ab..5b8201d 100644
--- a/lib/ogc/gml/curve_segment_array_property.rb
+++ b/lib/ogc/gml/curve_segment_array_property.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_curve_segment"
 require_relative "arc"
@@ -10,7 +10,7 @@
 
 module Ogc
   module Gml
-    class CurveSegmentArrayProperty < Shale::Mapper
+    class CurveSegmentArrayProperty < Lutaml::Model::Serializable
       attribute :abstract_curve_segment, AbstractCurveSegment, collection: true
       attribute :arc, Arc, collection: true
       attribute :arc_by_center_point, ArcByCenterPoint, collection: true
diff --git a/lib/ogc/gml/cylinder.rb b/lib/ogc/gml/cylinder.rb
index 3ed43d2..552bf7d 100644
--- a/lib/ogc/gml/cylinder.rb
+++ b/lib/ogc/gml/cylinder.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_gridded_surface"
 
 module Ogc
   module Gml
     class Cylinder < AbstractGriddedSurface
-      attribute :horizontal_curve_type, Shale::Type::String
-      attribute :vertical_curve_type, Shale::Type::String
+      attribute :horizontal_curve_type, :string
+      attribute :vertical_curve_type, :string
 
       xml do
         root "Cylinder"
diff --git a/lib/ogc/gml/cylindrical_cs.rb b/lib/ogc/gml/cylindrical_cs.rb
index ba684a0..6caebfe 100644
--- a/lib/ogc/gml/cylindrical_cs.rb
+++ b/lib/ogc/gml/cylindrical_cs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_system"
 
 module Ogc
diff --git a/lib/ogc/gml/cylindrical_cs_property.rb b/lib/ogc/gml/cylindrical_cs_property.rb
index 8a02573..a3ffe98 100644
--- a/lib/ogc/gml/cylindrical_cs_property.rb
+++ b/lib/ogc/gml/cylindrical_cs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "cylindrical_cs"
 
 module Ogc
   module Gml
-    class CylindricalCSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class CylindricalCSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :cylindrical_cs, CylindricalCS
 
       xml do
diff --git a/lib/ogc/gml/data_block.rb b/lib/ogc/gml/data_block.rb
index a59767c..b31d9dc 100644
--- a/lib/ogc/gml/data_block.rb
+++ b/lib/ogc/gml/data_block.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "association_role"
 require_relative "coordinates"
 
 module Ogc
   module Gml
-    class DataBlock < Shale::Mapper
+    class DataBlock < Lutaml::Model::Serializable
       attribute :range_parameters, AssociationRole
       attribute :tuple_list, Coordinates
-      attribute :double_or_nil_reason_tuple_list, Shale::Type::Value
+      attribute :double_or_nil_reason_tuple_list, :string
 
       xml do
         root "DataBlock"
diff --git a/lib/ogc/gml/datum_property.rb b/lib/ogc/gml/datum_property.rb
index c597101..bdd374d 100644
--- a/lib/ogc/gml/datum_property.rb
+++ b/lib/ogc/gml/datum_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_datum"
 
 module Ogc
   module Gml
-    class DatumProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class DatumProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_datum, AbstractDatum
 
       xml do
diff --git a/lib/ogc/gml/definition.rb b/lib/ogc/gml/definition.rb
index 067bfb2..d6871fb 100644
--- a/lib/ogc/gml/definition.rb
+++ b/lib/ogc/gml/definition.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -11,7 +11,7 @@
 module Ogc
   module Gml
     class Definition < AbstractTopology
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
 
       xml do
         root "Definition"
diff --git a/lib/ogc/gml/definition_proxy.rb b/lib/ogc/gml/definition_proxy.rb
index b0177bc..33fd77c 100644
--- a/lib/ogc/gml/definition_proxy.rb
+++ b/lib/ogc/gml/definition_proxy.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -11,7 +11,7 @@
 module Ogc
   module Gml
     class DefinitionProxy < AbstractTopology
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
       attribute :definition_ref, Reference
 
       xml do
diff --git a/lib/ogc/gml/degrees.rb b/lib/ogc/gml/degrees.rb
index 761e1c5..ac655e9 100644
--- a/lib/ogc/gml/degrees.rb
+++ b/lib/ogc/gml/degrees.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class Degrees < Shale::Mapper
-      attribute :content, Shale::Type::Integer
-      attribute :direction, Shale::Type::String
+    class Degrees < Lutaml::Model::Serializable
+      attribute :content, :integer
+      attribute :direction, :string
 
       xml do
         root "degrees"
diff --git a/lib/ogc/gml/derivation_unit_term.rb b/lib/ogc/gml/derivation_unit_term.rb
index 1d11b4c..bc02a57 100644
--- a/lib/ogc/gml/derivation_unit_term.rb
+++ b/lib/ogc/gml/derivation_unit_term.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class DerivationUnitTerm < Shale::Mapper
-      attribute :uom, Shale::Type::Value
-      attribute :exponent, Shale::Type::Integer
+    class DerivationUnitTerm < Lutaml::Model::Serializable
+      attribute :uom, :string
+      attribute :exponent, :integer
 
       xml do
         root "derivationUnitTerm"
diff --git a/lib/ogc/gml/derived_crs.rb b/lib/ogc/gml/derived_crs.rb
index 91cf5f8..d83e1a8 100644
--- a/lib/ogc/gml/derived_crs.rb
+++ b/lib/ogc/gml/derived_crs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "code_with_authority"
 require_relative "coordinate_system_property"
 require_relative "single_crs_property"
diff --git a/lib/ogc/gml/derived_crs_property.rb b/lib/ogc/gml/derived_crs_property.rb
index 2133ef8..c9b9b18 100644
--- a/lib/ogc/gml/derived_crs_property.rb
+++ b/lib/ogc/gml/derived_crs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "derived_crs"
 
 module Ogc
   module Gml
-    class DerivedCRSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class DerivedCRSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :derived_crs, DerivedCRS
 
       xml do
diff --git a/lib/ogc/gml/derived_unit.rb b/lib/ogc/gml/derived_unit.rb
index fd6522c..3be7beb 100644
--- a/lib/ogc/gml/derived_unit.rb
+++ b/lib/ogc/gml/derived_unit.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -13,7 +13,7 @@
 module Ogc
   module Gml
     class DerivedUnit < AbstractTopology
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
       attribute :quantity_type, StringOrRef
       attribute :quantity_type_reference, Reference
       attribute :catalog_symbol, Code
diff --git a/lib/ogc/gml/dictionary.rb b/lib/ogc/gml/dictionary.rb
index cedd582..09ff426 100644
--- a/lib/ogc/gml/dictionary.rb
+++ b/lib/ogc/gml/dictionary.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code_with_authority"
 require_relative "dictionary_entry"
@@ -10,18 +10,18 @@
 
 module Ogc
   module Gml
-    class Dictionary < Shale::Mapper
-      attribute :id, Shale::Type::String
-      attribute :aggregation_type, Shale::Type::String
+    class Dictionary < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :aggregation_type, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
-      attribute :name, Shale::Type::String, collection: true
-      attribute :remarks, Shale::Type::String
+      attribute :name, :string, collection: true
+      attribute :remarks, :string
       attribute :dictionary_entry, DictionaryEntry, collection: true
       attribute :indirect_entry, IndirectEntry, collection: true
-      attribute :schema_location, Shale::Type::String
+      attribute :schema_location, :string
 
       xml do
         root "Dictionary"
diff --git a/lib/ogc/gml/dictionary_entry.rb b/lib/ogc/gml/dictionary_entry.rb
index 03a5da6..4cd1e02 100644
--- a/lib/ogc/gml/dictionary_entry.rb
+++ b/lib/ogc/gml/dictionary_entry.rb
@@ -1,19 +1,19 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "definition"
 
 module Ogc
   module Gml
-    class DictionaryEntry < Shale::Mapper
-      attribute :id, Shale::Type::String
-      attribute :owns, Shale::Type::Boolean#, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class DictionaryEntry < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :owns, :boolean #, default: -> { "false" }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :definition, Definition
-      attribute :name, Shale::Type::String
-      attribute :description, Shale::Type::String
+      attribute :name, :string
+      attribute :description, :string
 
       xml do
         root "dictionaryEntry"
diff --git a/lib/ogc/gml/direct_position.rb b/lib/ogc/gml/direct_position.rb
index 3ead1c7..8b356f6 100644
--- a/lib/ogc/gml/direct_position.rb
+++ b/lib/ogc/gml/direct_position.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class DirectPosition < Shale::Mapper
-      attribute :content, Shale::Type::Value
-      attribute :srs_name, Shale::Type::Value
-      attribute :srs_dimension, Shale::Type::Integer
-      attribute :axis_labels, Shale::Type::Value
-      attribute :uom_labels, Shale::Type::Value
+    class DirectPosition < Lutaml::Model::Serializable
+      attribute :content, :string
+      attribute :srs_name, :string
+      attribute :srs_dimension, :integer
+      attribute :axis_labels, :string
+      attribute :uom_labels, :string
 
       xml do
         root "pos"
diff --git a/lib/ogc/gml/direct_position_list.rb b/lib/ogc/gml/direct_position_list.rb
index 0555fa0..3d517cd 100644
--- a/lib/ogc/gml/direct_position_list.rb
+++ b/lib/ogc/gml/direct_position_list.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class DirectPositionList < Shale::Mapper
-      attribute :content, Shale::Type::Value
-      attribute :srs_name, Shale::Type::Value
-      attribute :srs_dimension, Shale::Type::Integer
-      attribute :axis_labels, Shale::Type::Value
-      attribute :uom_labels, Shale::Type::Value
-      attribute :count, Shale::Type::Integer
+    class DirectPositionList < Lutaml::Model::Serializable
+      attribute :content, :string
+      attribute :srs_name, :string
+      attribute :srs_dimension, :integer
+      attribute :axis_labels, :string
+      attribute :uom_labels, :string
+      attribute :count, :integer
 
       xml do
         root "posList"
diff --git a/lib/ogc/gml/directed_edge_property.rb b/lib/ogc/gml/directed_edge_property.rb
index 4a92f96..82c97b0 100644
--- a/lib/ogc/gml/directed_edge_property.rb
+++ b/lib/ogc/gml/directed_edge_property.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "edge"
 
 module Ogc
   module Gml
-    class DirectedEdgeProperty < Shale::Mapper
-      attribute :orientation, Shale::Type::String, default: -> { "+" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class DirectedEdgeProperty < Lutaml::Model::Serializable
+      attribute :orientation, :string, default: -> { "+" }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :edge, Edge
 
       xml do
diff --git a/lib/ogc/gml/directed_face_property.rb b/lib/ogc/gml/directed_face_property.rb
index bdbdd3e..ac1ac9b 100644
--- a/lib/ogc/gml/directed_face_property.rb
+++ b/lib/ogc/gml/directed_face_property.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "face"
 
 module Ogc
   module Gml
-    class DirectedFaceProperty < Shale::Mapper
-      attribute :orientation, Shale::Type::String, default: -> { "+" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class DirectedFaceProperty < Lutaml::Model::Serializable
+      attribute :orientation, :string, default: -> { "+" }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :face, Face
 
       xml do
diff --git a/lib/ogc/gml/directed_node_property.rb b/lib/ogc/gml/directed_node_property.rb
index 0a3e6e5..6d5d990 100644
--- a/lib/ogc/gml/directed_node_property.rb
+++ b/lib/ogc/gml/directed_node_property.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "node"
 
 module Ogc
   module Gml
-    class DirectedNodeProperty < Shale::Mapper
-      attribute :orientation, Shale::Type::String, default: -> { "+" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class DirectedNodeProperty < Lutaml::Model::Serializable
+      attribute :orientation, :string, default: -> { "+" }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :node, Node
 
       xml do
diff --git a/lib/ogc/gml/directed_observation.rb b/lib/ogc/gml/directed_observation.rb
index 16980e7..78ecab4 100644
--- a/lib/ogc/gml/directed_observation.rb
+++ b/lib/ogc/gml/directed_observation.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "bounding_shape"
 require_relative "code"
diff --git a/lib/ogc/gml/directed_observation_at_distance.rb b/lib/ogc/gml/directed_observation_at_distance.rb
index 3172b1e..e5f1a8d 100644
--- a/lib/ogc/gml/directed_observation_at_distance.rb
+++ b/lib/ogc/gml/directed_observation_at_distance.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "bounding_shape"
 require_relative "code"
diff --git a/lib/ogc/gml/directed_topo_solid_property.rb b/lib/ogc/gml/directed_topo_solid_property.rb
index 9da0c39..7d93840 100644
--- a/lib/ogc/gml/directed_topo_solid_property.rb
+++ b/lib/ogc/gml/directed_topo_solid_property.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "topo_solid"
 
 module Ogc
   module Gml
-    class DirectedTopoSolidProperty < Shale::Mapper
-      attribute :orientation, Shale::Type::String, default: -> { "+" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class DirectedTopoSolidProperty < Lutaml::Model::Serializable
+      attribute :orientation, :string, default: -> { "+" }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :topo_solid, TopoSolid
 
       xml do
diff --git a/lib/ogc/gml/direction_description.rb b/lib/ogc/gml/direction_description.rb
index ed1cae0..cad44db 100644
--- a/lib/ogc/gml/direction_description.rb
+++ b/lib/ogc/gml/direction_description.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "reference"
 
 module Ogc
   module Gml
-    class DirectionDescription < Shale::Mapper
-      attribute :compass_point, Shale::Type::String
+    class DirectionDescription < Lutaml::Model::Serializable
+      attribute :compass_point, :string
       attribute :keyword, Code
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :reference, Reference
 
       xml do
diff --git a/lib/ogc/gml/direction_property.rb b/lib/ogc/gml/direction_property.rb
index defa45b..e4a6d29 100644
--- a/lib/ogc/gml/direction_property.rb
+++ b/lib/ogc/gml/direction_property.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "direction_description"
@@ -9,13 +9,13 @@
 
 module Ogc
   module Gml
-    class DirectionProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class DirectionProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :direction_vector, DirectionVector
       attribute :direction_description, DirectionDescription
-      attribute :compass_point, Shale::Type::String
+      attribute :compass_point, :string
       attribute :direction_keyword, Code
       attribute :direction_string, StringOrRef
 
diff --git a/lib/ogc/gml/direction_vector.rb b/lib/ogc/gml/direction_vector.rb
index 04e0a1c..dcdca59 100644
--- a/lib/ogc/gml/direction_vector.rb
+++ b/lib/ogc/gml/direction_vector.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "angle"
 require_relative "vector"
 
 module Ogc
   module Gml
-    class DirectionVector < Shale::Mapper
+    class DirectionVector < Lutaml::Model::Serializable
       attribute :vector, Vector
       attribute :horizontal_angle, Angle
       attribute :vertical_angle, Angle
diff --git a/lib/ogc/gml/discrete_coverage.rb b/lib/ogc/gml/discrete_coverage.rb
index ec25408..f0b21e4 100644
--- a/lib/ogc/gml/discrete_coverage.rb
+++ b/lib/ogc/gml/discrete_coverage.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_continuous_coverage"
 
 module Ogc
diff --git a/lib/ogc/gml/dms_angle.rb b/lib/ogc/gml/dms_angle.rb
index 6137087..c67f19e 100644
--- a/lib/ogc/gml/dms_angle.rb
+++ b/lib/ogc/gml/dms_angle.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "degrees"
 
 module Ogc
   module Gml
-    class DMSAngle < Shale::Mapper
+    class DMSAngle < Lutaml::Model::Serializable
       attribute :degrees, Degrees
-      attribute :decimal_minutes, Shale::Type::Float
-      attribute :minutes, Shale::Type::Integer
-      attribute :seconds, Shale::Type::Float
+      attribute :decimal_minutes, :float
+      attribute :minutes, :integer
+      attribute :seconds, :float
 
       xml do
         root "dmsAngle"
diff --git a/lib/ogc/gml/domain_of_validity.rb b/lib/ogc/gml/domain_of_validity.rb
index a5c736e..5782250 100644
--- a/lib/ogc/gml/domain_of_validity.rb
+++ b/lib/ogc/gml/domain_of_validity.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "string_or_ref"
 
 module Ogc
   module Gml
-    class DomainOfValidity < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class DomainOfValidity < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :ex_extent, StringOrRef
 
       xml do
diff --git a/lib/ogc/gml/domain_set.rb b/lib/ogc/gml/domain_set.rb
index 8cacc1f..34cfff1 100644
--- a/lib/ogc/gml/domain_set.rb
+++ b/lib/ogc/gml/domain_set.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_geometry"
 require_relative "abstract_time_object"
 
 module Ogc
   module Gml
-    class DomainSet < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class DomainSet < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_geometry, AbstractGeometry
       attribute :abstract_time_object, AbstractTimeObject
 
diff --git a/lib/ogc/gml/dynamic_feature.rb b/lib/ogc/gml/dynamic_feature.rb
index a0dd527..67069b4 100644
--- a/lib/ogc/gml/dynamic_feature.rb
+++ b/lib/ogc/gml/dynamic_feature.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "bounding_shape"
 require_relative "code"
diff --git a/lib/ogc/gml/dynamic_feature_collection.rb b/lib/ogc/gml/dynamic_feature_collection.rb
index 9926f14..01343da 100644
--- a/lib/ogc/gml/dynamic_feature_collection.rb
+++ b/lib/ogc/gml/dynamic_feature_collection.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "bounding_shape"
 require_relative "code"
diff --git a/lib/ogc/gml/dynamic_feature_member.rb b/lib/ogc/gml/dynamic_feature_member.rb
index 64b58b6..ad8636a 100644
--- a/lib/ogc/gml/dynamic_feature_member.rb
+++ b/lib/ogc/gml/dynamic_feature_member.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "dynamic_feature"
 
 module Ogc
   module Gml
-    class DynamicFeatureMember < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class DynamicFeatureMember < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :dynamic_feature, DynamicFeature, collection: true
 
       xml do
diff --git a/lib/ogc/gml/edge.rb b/lib/ogc/gml/edge.rb
index 9b5f4bf..48c6646 100644
--- a/lib/ogc/gml/edge.rb
+++ b/lib/ogc/gml/edge.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -13,11 +13,11 @@
 
 module Ogc
   module Gml
-    class Edge < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :aggregation_type, Shale::Type::String
+    class Edge < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :aggregation_type, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/ellipsoid.rb b/lib/ogc/gml/ellipsoid.rb
index f3ab5a3..b9dc57b 100644
--- a/lib/ogc/gml/ellipsoid.rb
+++ b/lib/ogc/gml/ellipsoid.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -13,7 +13,7 @@
 module Ogc
   module Gml
     class Ellipsoid < AbstractTopology
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
       attribute :semi_major_axis, Measure
       attribute :second_defining_parameter, SecondDefiningParameter1
 
diff --git a/lib/ogc/gml/ellipsoid_property.rb b/lib/ogc/gml/ellipsoid_property.rb
index 5854eb2..5f0cf82 100644
--- a/lib/ogc/gml/ellipsoid_property.rb
+++ b/lib/ogc/gml/ellipsoid_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "ellipsoid"
 
 module Ogc
   module Gml
-    class EllipsoidProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class EllipsoidProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :ellipsoid, Ellipsoid
 
       xml do
diff --git a/lib/ogc/gml/ellipsoidal_cs.rb b/lib/ogc/gml/ellipsoidal_cs.rb
index c31b768..f043a5e 100644
--- a/lib/ogc/gml/ellipsoidal_cs.rb
+++ b/lib/ogc/gml/ellipsoidal_cs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_system"
 
 module Ogc
diff --git a/lib/ogc/gml/ellipsoidal_cs_property.rb b/lib/ogc/gml/ellipsoidal_cs_property.rb
index b15c872..fe84713 100644
--- a/lib/ogc/gml/ellipsoidal_cs_property.rb
+++ b/lib/ogc/gml/ellipsoidal_cs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "ellipsoidal_cs"
 
 module Ogc
   module Gml
-    class EllipsoidalCSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class EllipsoidalCSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :ellipsoidal_cs, EllipsoidalCS
 
       xml do
diff --git a/lib/ogc/gml/engineering_crs.rb b/lib/ogc/gml/engineering_crs.rb
index 67e7fc7..3e65f9b 100644
--- a/lib/ogc/gml/engineering_crs.rb
+++ b/lib/ogc/gml/engineering_crs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "affine_cs_property"
 require_relative "cartesian_cs_property"
 require_relative "coordinate_system_property"
diff --git a/lib/ogc/gml/engineering_crs_property.rb b/lib/ogc/gml/engineering_crs_property.rb
index e111b40..403b046 100644
--- a/lib/ogc/gml/engineering_crs_property.rb
+++ b/lib/ogc/gml/engineering_crs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "engineering_crs"
 
 module Ogc
   module Gml
-    class EngineeringCRSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class EngineeringCRSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :engineering_crs, EngineeringCRS
 
       xml do
diff --git a/lib/ogc/gml/engineering_datum.rb b/lib/ogc/gml/engineering_datum.rb
index 44e5bb7..20e884c 100644
--- a/lib/ogc/gml/engineering_datum.rb
+++ b/lib/ogc/gml/engineering_datum.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_datum"
 
 module Ogc
diff --git a/lib/ogc/gml/engineering_datum_property.rb b/lib/ogc/gml/engineering_datum_property.rb
index e6bb4b6..f3a4d86 100644
--- a/lib/ogc/gml/engineering_datum_property.rb
+++ b/lib/ogc/gml/engineering_datum_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "engineering_datum"
 
 module Ogc
   module Gml
-    class EngineeringDatumProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class EngineeringDatumProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :engineering_datum, EngineeringDatum
 
       xml do
diff --git a/lib/ogc/gml/envelope.rb b/lib/ogc/gml/envelope.rb
index 0da2219..a95c71e 100644
--- a/lib/ogc/gml/envelope.rb
+++ b/lib/ogc/gml/envelope.rb
@@ -1,17 +1,17 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "coordinates"
 require_relative "direct_position"
 
 module Ogc
   module Gml
-    class Envelope < Shale::Mapper
-      attribute :srs_name, Shale::Type::Value
-      attribute :srs_dimension, Shale::Type::Integer
-      attribute :axis_labels, Shale::Type::Value
-      attribute :uom_labels, Shale::Type::Value
+    class Envelope < Lutaml::Model::Serializable
+      attribute :srs_name, :string
+      attribute :srs_dimension, :integer
+      attribute :axis_labels, :string
+      attribute :uom_labels, :string
       attribute :lower_corner, DirectPosition
       attribute :upper_corner, DirectPosition
       attribute :pos, DirectPosition, collection: true
diff --git a/lib/ogc/gml/envelope_with_time_period.rb b/lib/ogc/gml/envelope_with_time_period.rb
index ac97ad6..22d9bb3 100644
--- a/lib/ogc/gml/envelope_with_time_period.rb
+++ b/lib/ogc/gml/envelope_with_time_period.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "coordinates"
 require_relative "direct_position"
@@ -8,12 +8,12 @@
 
 module Ogc
   module Gml
-    class EnvelopeWithTimePeriod < Shale::Mapper
-      attribute :srs_name, Shale::Type::Value
-      attribute :srs_dimension, Shale::Type::Integer
-      attribute :axis_labels, Shale::Type::Value
-      attribute :uom_labels, Shale::Type::Value
-      attribute :frame, Shale::Type::Value, default: -> { "#ISO-8601" }
+    class EnvelopeWithTimePeriod < Lutaml::Model::Serializable
+      attribute :srs_name, :string
+      attribute :srs_dimension, :integer
+      attribute :axis_labels, :string
+      attribute :uom_labels, :string
+      attribute :frame, :string, default: -> { "#ISO-8601" }
       attribute :lower_corner, DirectPosition
       attribute :upper_corner, DirectPosition
       attribute :pos, DirectPosition, collection: true
diff --git a/lib/ogc/gml/face.rb b/lib/ogc/gml/face.rb
index ec95f4a..12ee208 100644
--- a/lib/ogc/gml/face.rb
+++ b/lib/ogc/gml/face.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -13,12 +13,12 @@
 
 module Ogc
   module Gml
-    class Face < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :aggregation_type, Shale::Type::String
-      attribute :universal, Shale::Type::Boolean, default: -> { "false" }
+    class Face < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :aggregation_type, :string
+      attribute :universal, :boolean, default: -> { false }
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/face_or_topo_solid_property.rb b/lib/ogc/gml/face_or_topo_solid_property.rb
index 69b3f7c..976c75e 100644
--- a/lib/ogc/gml/face_or_topo_solid_property.rb
+++ b/lib/ogc/gml/face_or_topo_solid_property.rb
@@ -1,19 +1,19 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 # require_relative "face"
 # require_relative "topo_solid"
 
 module Ogc
   module Gml
-    class Face < Shale::Mapper; end
-    class TopoSolid < Shale::Mapper; end
+    class Face < Lutaml::Model::Serializable; end
+    class TopoSolid < Lutaml::Model::Serializable; end
 
-    class FaceOrTopoSolidProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class FaceOrTopoSolidProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :face, Face
       attribute :topo_solid, TopoSolid
 
diff --git a/lib/ogc/gml/feature_array_property.rb b/lib/ogc/gml/feature_array_property.rb
index 5b973e6..cf96928 100644
--- a/lib/ogc/gml/feature_array_property.rb
+++ b/lib/ogc/gml/feature_array_property.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_feature"
 
 module Ogc
   module Gml
-    class FeatureArrayProperty < Shale::Mapper
+    class FeatureArrayProperty < Lutaml::Model::Serializable
       attribute :abstract_feature, AbstractFeature, collection: true
 
       xml do
diff --git a/lib/ogc/gml/feature_collection.rb b/lib/ogc/gml/feature_collection.rb
index dbdfbf7..75814b5 100644
--- a/lib/ogc/gml/feature_collection.rb
+++ b/lib/ogc/gml/feature_collection.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_feature_collection"
 
 module Ogc
diff --git a/lib/ogc/gml/feature_property.rb b/lib/ogc/gml/feature_property.rb
index 8c58a0e..217b23e 100644
--- a/lib/ogc/gml/feature_property.rb
+++ b/lib/ogc/gml/feature_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_feature"
 
 module Ogc
   module Gml
-    class FeatureProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class FeatureProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_feature, AbstractFeature
 
       xml do
diff --git a/lib/ogc/gml/file.rb b/lib/ogc/gml/file.rb
index 7f3d324..f351a17 100644
--- a/lib/ogc/gml/file.rb
+++ b/lib/ogc/gml/file.rb
@@ -1,19 +1,19 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "association_role"
 require_relative "code"
 
 module Ogc
   module Gml
-    class File < Shale::Mapper
+    class File < Lutaml::Model::Serializable
       attribute :range_parameters, AssociationRole
-      attribute :file_name, Shale::Type::Value
-      attribute :file_reference, Shale::Type::Value
+      attribute :file_name, :string
+      attribute :file_reference, :string
       attribute :file_structure, Code
-      attribute :mime_type, Shale::Type::Value
-      attribute :compression, Shale::Type::Value
+      attribute :mime_type, :string
+      attribute :compression, :string
 
       xml do
         root "File"
diff --git a/lib/ogc/gml/formula.rb b/lib/ogc/gml/formula.rb
index 6e840a9..cad04d4 100644
--- a/lib/ogc/gml/formula.rb
+++ b/lib/ogc/gml/formula.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class Formula < Shale::Mapper
-      attribute :a, Shale::Type::Float
-      attribute :b, Shale::Type::Float
-      attribute :c, Shale::Type::Float
-      attribute :d, Shale::Type::Float
+    class Formula < Lutaml::Model::Serializable
+      attribute :a, :float
+      attribute :b, :float
+      attribute :c, :float
+      attribute :d, :float
 
       xml do
         root "FormulaType"
diff --git a/lib/ogc/gml/formula_citation.rb b/lib/ogc/gml/formula_citation.rb
index e168ebd..073f1ea 100644
--- a/lib/ogc/gml/formula_citation.rb
+++ b/lib/ogc/gml/formula_citation.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "string_or_ref"
 
 module Ogc
   module Gml
-    class FormulaCitation < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class FormulaCitation < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :reference_event, StringOrRef
 
       xml do
diff --git a/lib/ogc/gml/general_conversion_property.rb b/lib/ogc/gml/general_conversion_property.rb
index a3b9c00..056baac 100644
--- a/lib/ogc/gml/general_conversion_property.rb
+++ b/lib/ogc/gml/general_conversion_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_general_conversion"
 
 module Ogc
   module Gml
-    class GeneralConversionProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class GeneralConversionProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_general_conversion, AbstractGeneralConversion
 
       xml do
diff --git a/lib/ogc/gml/general_transformation_property.rb b/lib/ogc/gml/general_transformation_property.rb
index bd38b52..390a3f3 100644
--- a/lib/ogc/gml/general_transformation_property.rb
+++ b/lib/ogc/gml/general_transformation_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_general_transformation"
 
 module Ogc
   module Gml
-    class GeneralTransformationProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class GeneralTransformationProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_general_transformation, AbstractGeneralTransformation
 
       xml do
diff --git a/lib/ogc/gml/generic_meta_data.rb b/lib/ogc/gml/generic_meta_data.rb
index 417fb40..4249819 100644
--- a/lib/ogc/gml/generic_meta_data.rb
+++ b/lib/ogc/gml/generic_meta_data.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class GenericMetaData < Shale::Mapper
-      attribute :content, Shale::Type::String
-      attribute :id, Shale::Type::Value
+    class GenericMetaData < Lutaml::Model::Serializable
+      attribute :content, :string
+      attribute :id, :string
 
       xml do
         root "GenericMetaData"
diff --git a/lib/ogc/gml/geocentric_crs.rb b/lib/ogc/gml/geocentric_crs.rb
index 0ce918f..eed70ce 100644
--- a/lib/ogc/gml/geocentric_crs.rb
+++ b/lib/ogc/gml/geocentric_crs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "cartesian_cs_property"
 require_relative "geodetic_datum_property"
 require_relative "spherical_cs_property"
diff --git a/lib/ogc/gml/geocentric_crs_property.rb b/lib/ogc/gml/geocentric_crs_property.rb
index 5626559..f1bee2f 100644
--- a/lib/ogc/gml/geocentric_crs_property.rb
+++ b/lib/ogc/gml/geocentric_crs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "geocentric_crs"
 
 module Ogc
   module Gml
-    class GeocentricCRSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class GeocentricCRSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :geocentric_crs, GeocentricCRS
 
       xml do
diff --git a/lib/ogc/gml/geodesic.rb b/lib/ogc/gml/geodesic.rb
index 585e2e4..fb4e938 100644
--- a/lib/ogc/gml/geodesic.rb
+++ b/lib/ogc/gml/geodesic.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "direct_position_list"
 require_relative "direct_position"
@@ -10,7 +10,7 @@
 module Ogc
   module Gml
     class Geodesic < AbstractCurveSegment
-      attribute :interpolation, Shale::Type::String
+      attribute :interpolation, :string
       attribute :pos_list, DirectPositionList
       attribute :pos, DirectPosition, collection: true
       attribute :point_property, PointProperty, collection: true
diff --git a/lib/ogc/gml/geodesic_string.rb b/lib/ogc/gml/geodesic_string.rb
index 90b9ea1..edd9d87 100644
--- a/lib/ogc/gml/geodesic_string.rb
+++ b/lib/ogc/gml/geodesic_string.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "direct_position_list"
 require_relative "direct_position"
@@ -10,7 +10,7 @@
 module Ogc
   module Gml
     class GeodesicString < AbstractCurveSegment
-      attribute :interpolation, Shale::Type::String
+      attribute :interpolation, :string
       attribute :pos_list, DirectPositionList
       attribute :pos, DirectPosition, collection: true
       attribute :point_property, PointProperty, collection: true
diff --git a/lib/ogc/gml/geodetic_crs.rb b/lib/ogc/gml/geodetic_crs.rb
index 34801c4..e303617 100644
--- a/lib/ogc/gml/geodetic_crs.rb
+++ b/lib/ogc/gml/geodetic_crs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "cartesian_cs_property"
 require_relative "ellipsoidal_cs_property"
diff --git a/lib/ogc/gml/geodetic_crs_property.rb b/lib/ogc/gml/geodetic_crs_property.rb
index e92b455..ef1e7a1 100644
--- a/lib/ogc/gml/geodetic_crs_property.rb
+++ b/lib/ogc/gml/geodetic_crs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "geodetic_crs"
 
 module Ogc
   module Gml
-    class GeodeticCRSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class GeodeticCRSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :geodetic_crs, GeodeticCRS
 
       xml do
diff --git a/lib/ogc/gml/geodetic_datum.rb b/lib/ogc/gml/geodetic_datum.rb
index e93d925..2622a9c 100644
--- a/lib/ogc/gml/geodetic_datum.rb
+++ b/lib/ogc/gml/geodetic_datum.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "ellipsoid_property"
 require_relative "prime_meridian_property"
 require_relative "abstract_datum"
diff --git a/lib/ogc/gml/geodetic_datum_property.rb b/lib/ogc/gml/geodetic_datum_property.rb
index ab4dea7..f378df0 100644
--- a/lib/ogc/gml/geodetic_datum_property.rb
+++ b/lib/ogc/gml/geodetic_datum_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "geodetic_datum"
 
 module Ogc
   module Gml
-    class GeodeticDatumProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class GeodeticDatumProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :geodetic_datum, GeodeticDatum
 
       xml do
diff --git a/lib/ogc/gml/geographic_crs.rb b/lib/ogc/gml/geographic_crs.rb
index b20ee37..205e2c0 100644
--- a/lib/ogc/gml/geographic_crs.rb
+++ b/lib/ogc/gml/geographic_crs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "ellipsoidal_cs_property"
 require_relative "geodetic_datum_property"
 require_relative "abstract_crs"
diff --git a/lib/ogc/gml/geographic_crs_property.rb b/lib/ogc/gml/geographic_crs_property.rb
index 9b5bc2b..200bc59 100644
--- a/lib/ogc/gml/geographic_crs_property.rb
+++ b/lib/ogc/gml/geographic_crs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "geographic_crs"
 
 module Ogc
   module Gml
-    class GeographicCRSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class GeographicCRSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :geographic_crs, GeographicCRS
 
       xml do
diff --git a/lib/ogc/gml/geometric_complex.rb b/lib/ogc/gml/geometric_complex.rb
index 9dcce63..34c0b9f 100644
--- a/lib/ogc/gml/geometric_complex.rb
+++ b/lib/ogc/gml/geometric_complex.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "geometric_primitive_property"
 require_relative "abstract_geometric_aggregate"
 
diff --git a/lib/ogc/gml/geometric_primitive_property.rb b/lib/ogc/gml/geometric_primitive_property.rb
index ec9d083..81ef9ba 100644
--- a/lib/ogc/gml/geometric_primitive_property.rb
+++ b/lib/ogc/gml/geometric_primitive_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_geometric_primitive"
 
 module Ogc
   module Gml
-    class GeometricPrimitiveProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class GeometricPrimitiveProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_geometric_primitive, AbstractGeometricPrimitive
 
       xml do
diff --git a/lib/ogc/gml/geometry_array_property.rb b/lib/ogc/gml/geometry_array_property.rb
index 78e9793..a26f744 100644
--- a/lib/ogc/gml/geometry_array_property.rb
+++ b/lib/ogc/gml/geometry_array_property.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_geometry"
 
 module Ogc
   module Gml
-    class GeometryArrayProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class GeometryArrayProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
       attribute :abstract_geometry, AbstractGeometry, collection: true
 
       xml do
diff --git a/lib/ogc/gml/geometry_property.rb b/lib/ogc/gml/geometry_property.rb
index 503a932..87af49c 100644
--- a/lib/ogc/gml/geometry_property.rb
+++ b/lib/ogc/gml/geometry_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_geometry"
 
 module Ogc
   module Gml
-    class GeometryProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class GeometryProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :abstract_geometry, AbstractGeometry
 
       xml do
diff --git a/lib/ogc/gml/grid.rb b/lib/ogc/gml/grid.rb
index 48704fb..822273d 100644
--- a/lib/ogc/gml/grid.rb
+++ b/lib/ogc/gml/grid.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -10,20 +10,20 @@
 
 module Ogc
   module Gml
-    class Grid < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :srs_name, Shale::Type::Value
-      attribute :srs_dimension, Shale::Type::Integer
-      attribute :axis_labels, Shale::Type::Value
-      attribute :uom_labels, Shale::Type::Value
-      attribute :dimension, Shale::Type::Integer
+    class Grid < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :srs_name, :string
+      attribute :srs_dimension, :integer
+      attribute :axis_labels, :string
+      attribute :uom_labels, :string
+      attribute :dimension, :integer
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
       attribute :limits, GridLimits
-      attribute :axis_name, Shale::Type::String, collection: true
+      attribute :axis_name, :string, collection: true
 
       xml do
         root "Grid"
diff --git a/lib/ogc/gml/grid_envelope.rb b/lib/ogc/gml/grid_envelope.rb
index acb93cc..0c20137 100644
--- a/lib/ogc/gml/grid_envelope.rb
+++ b/lib/ogc/gml/grid_envelope.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class GridEnvelope < Shale::Mapper
-      attribute :low, Shale::Type::Value
-      attribute :high, Shale::Type::Value
+    class GridEnvelope < Lutaml::Model::Serializable
+      attribute :low, :string
+      attribute :high, :string
 
       xml do
         root "GridEnvelopeType"
diff --git a/lib/ogc/gml/grid_function.rb b/lib/ogc/gml/grid_function.rb
index 4562917..bff1942 100644
--- a/lib/ogc/gml/grid_function.rb
+++ b/lib/ogc/gml/grid_function.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "sequence_rule"
 
 module Ogc
   module Gml
-    class GridFunction < Shale::Mapper
+    class GridFunction < Lutaml::Model::Serializable
       attribute :sequence_rule, SequenceRule
-      attribute :start_point, Shale::Type::Value
+      attribute :start_point, :string
 
       xml do
         root "GridFunction"
diff --git a/lib/ogc/gml/grid_limits.rb b/lib/ogc/gml/grid_limits.rb
index 656400b..dcda130 100644
--- a/lib/ogc/gml/grid_limits.rb
+++ b/lib/ogc/gml/grid_limits.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "grid_envelope"
 
 module Ogc
   module Gml
-    class GridLimits < Shale::Mapper
+    class GridLimits < Lutaml::Model::Serializable
       attribute :grid_envelope, GridEnvelope
 
       xml do
diff --git a/lib/ogc/gml/history_property.rb b/lib/ogc/gml/history_property.rb
index 5c2b67d..5a1d144 100644
--- a/lib/ogc/gml/history_property.rb
+++ b/lib/ogc/gml/history_property.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_time_slice"
 
 module Ogc
   module Gml
-    class HistoryProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class HistoryProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
       attribute :abstract_time_slice, AbstractTimeSlice, collection: true
 
       xml do
diff --git a/lib/ogc/gml/image_crs.rb b/lib/ogc/gml/image_crs.rb
index 2208eed..a89c024 100644
--- a/lib/ogc/gml/image_crs.rb
+++ b/lib/ogc/gml/image_crs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "affine_cs_property"
 require_relative "cartesian_cs_property"
 require_relative "image_datum_property"
diff --git a/lib/ogc/gml/image_crs_property.rb b/lib/ogc/gml/image_crs_property.rb
index 5687d58..634ce3a 100644
--- a/lib/ogc/gml/image_crs_property.rb
+++ b/lib/ogc/gml/image_crs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "image_crs"
 
 module Ogc
   module Gml
-    class ImageCRSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class ImageCRSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :image_crs, ImageCRS
 
       xml do
diff --git a/lib/ogc/gml/image_datum.rb b/lib/ogc/gml/image_datum.rb
index 2b2730e..8c44f4c 100644
--- a/lib/ogc/gml/image_datum.rb
+++ b/lib/ogc/gml/image_datum.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_datum"
 
 module Ogc
diff --git a/lib/ogc/gml/image_datum_property.rb b/lib/ogc/gml/image_datum_property.rb
index b22f4d1..ab103ed 100644
--- a/lib/ogc/gml/image_datum_property.rb
+++ b/lib/ogc/gml/image_datum_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "image_datum"
 
 module Ogc
   module Gml
-    class ImageDatumProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class ImageDatumProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :image_datum, ImageDatum
 
       xml do
diff --git a/lib/ogc/gml/indirect_entry.rb b/lib/ogc/gml/indirect_entry.rb
index 271f449..257f290 100644
--- a/lib/ogc/gml/indirect_entry.rb
+++ b/lib/ogc/gml/indirect_entry.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "definition_proxy"
 
 module Ogc
   module Gml
-    class IndirectEntry < Shale::Mapper
+    class IndirectEntry < Lutaml::Model::Serializable
       attribute :definition_proxy, DefinitionProxy
 
       xml do
diff --git a/lib/ogc/gml/inline_property.rb b/lib/ogc/gml/inline_property.rb
index b69818e..42b1005 100644
--- a/lib/ogc/gml/inline_property.rb
+++ b/lib/ogc/gml/inline_property.rb
@@ -1,11 +1,11 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class InlineProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class InlineProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
 
       xml do
         root "abstractInlineProperty"
diff --git a/lib/ogc/gml/knot.rb b/lib/ogc/gml/knot.rb
index 900d9ec..7e1c26f 100644
--- a/lib/ogc/gml/knot.rb
+++ b/lib/ogc/gml/knot.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class Knot < Shale::Mapper
-      attribute :value, Shale::Type::Float
-      attribute :multiplicity, Shale::Type::Integer
-      attribute :weight, Shale::Type::Float
+    class Knot < Lutaml::Model::Serializable
+      attribute :value, :float
+      attribute :multiplicity, :integer
+      attribute :weight, :float
 
       xml do
         root "KnotType"
diff --git a/lib/ogc/gml/knot_property.rb b/lib/ogc/gml/knot_property.rb
index 508e5f1..8a50401 100644
--- a/lib/ogc/gml/knot_property.rb
+++ b/lib/ogc/gml/knot_property.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "knot"
 
 module Ogc
   module Gml
-    class KnotProperty < Shale::Mapper
+    class KnotProperty < Lutaml::Model::Serializable
       attribute :knot, Knot
 
       xml do
diff --git a/lib/ogc/gml/length.rb b/lib/ogc/gml/length.rb
index e7d8bbf..dd73c62 100644
--- a/lib/ogc/gml/length.rb
+++ b/lib/ogc/gml/length.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "measure"
 
 module Ogc
   module Gml
-    class Length < Shale::Mapper
+    class Length < Lutaml::Model::Serializable
       attribute :content, Measure
 
       xml do
diff --git a/lib/ogc/gml/line_string.rb b/lib/ogc/gml/line_string.rb
index 651d028..50ec9c2 100644
--- a/lib/ogc/gml/line_string.rb
+++ b/lib/ogc/gml/line_string.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "coordinates"
 require_relative "direct_position_list"
diff --git a/lib/ogc/gml/line_string_segment.rb b/lib/ogc/gml/line_string_segment.rb
index f61fc78..9838110 100644
--- a/lib/ogc/gml/line_string_segment.rb
+++ b/lib/ogc/gml/line_string_segment.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "coordinates"
 require_relative "direct_position_list"
@@ -11,7 +11,7 @@
 module Ogc
   module Gml
     class LineStringSegment < AbstractCurveSegment
-      attribute :interpolation, Shale::Type::String
+      attribute :interpolation, :string
       attribute :pos, DirectPosition, collection: true
       attribute :point_property, PointProperty, collection: true
       attribute :point_rep, PointProperty, collection: true
diff --git a/lib/ogc/gml/line_string_segment_array_property.rb b/lib/ogc/gml/line_string_segment_array_property.rb
index 58a70e1..d7b3bbd 100644
--- a/lib/ogc/gml/line_string_segment_array_property.rb
+++ b/lib/ogc/gml/line_string_segment_array_property.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "line_string_segment"
 
 module Ogc
   module Gml
-    class LineStringSegmentArrayProperty < Shale::Mapper
+    class LineStringSegmentArrayProperty < Lutaml::Model::Serializable
       attribute :line_string_segment, LineStringSegment, collection: true
 
       xml do
diff --git a/lib/ogc/gml/linear_cs.rb b/lib/ogc/gml/linear_cs.rb
index 0e31807..cf96b9d 100644
--- a/lib/ogc/gml/linear_cs.rb
+++ b/lib/ogc/gml/linear_cs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_system"
 
 module Ogc
diff --git a/lib/ogc/gml/linear_cs_property.rb b/lib/ogc/gml/linear_cs_property.rb
index f6af0cf..f0560e7 100644
--- a/lib/ogc/gml/linear_cs_property.rb
+++ b/lib/ogc/gml/linear_cs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "linear_cs"
 
 module Ogc
   module Gml
-    class LinearCSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class LinearCSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :linear_cs, LinearCS
 
       xml do
diff --git a/lib/ogc/gml/linear_ring.rb b/lib/ogc/gml/linear_ring.rb
index 8112e70..e0e0655 100644
--- a/lib/ogc/gml/linear_ring.rb
+++ b/lib/ogc/gml/linear_ring.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "coordinates"
 require_relative "direct_position_list"
@@ -9,7 +9,7 @@
 
 module Ogc
   module Gml
-    class LinearRing < Shale::Mapper
+    class LinearRing < Lutaml::Model::Serializable
       attribute :pos, DirectPosition, collection: true
       attribute :point_property, PointProperty, collection: true
       attribute :point_rep, PointProperty, collection: true
diff --git a/lib/ogc/gml/location_property.rb b/lib/ogc/gml/location_property.rb
index 9307e6a..7038157 100644
--- a/lib/ogc/gml/location_property.rb
+++ b/lib/ogc/gml/location_property.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_geometry"
 require_relative "code"
@@ -8,13 +8,13 @@
 
 module Ogc
   module Gml
-    class LocationProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class LocationProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_geometry, AbstractGeometry
       attribute :location_key_word, Code
       attribute :location_string, StringOrRef
-      attribute :null, Shale::Type::Value
+      attribute :null, :string
 
       xml do
         root "location"
diff --git a/lib/ogc/gml/mapping_rule.rb b/lib/ogc/gml/mapping_rule.rb
index 1b14514..fb710d4 100644
--- a/lib/ogc/gml/mapping_rule.rb
+++ b/lib/ogc/gml/mapping_rule.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "reference"
 
 module Ogc
   module Gml
-    class MappingRule < Shale::Mapper
-      attribute :rule_definition, Shale::Type::String
+    class MappingRule < Lutaml::Model::Serializable
+      attribute :rule_definition, :string
       attribute :rule_reference, Reference
 
       xml do
diff --git a/lib/ogc/gml/measure.rb b/lib/ogc/gml/measure.rb
index b3433d6..10b38ba 100644
--- a/lib/ogc/gml/measure.rb
+++ b/lib/ogc/gml/measure.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class Measure < Shale::Mapper
-      attribute :content, Shale::Type::Float
-      attribute :uom, Shale::Type::Value
+    class Measure < Lutaml::Model::Serializable
+      attribute :content, :float
+      attribute :uom, :string
 
       xml do
         root "value"
diff --git a/lib/ogc/gml/measure_list.rb b/lib/ogc/gml/measure_list.rb
index 8d08e13..7360110 100644
--- a/lib/ogc/gml/measure_list.rb
+++ b/lib/ogc/gml/measure_list.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class MeasureList < Shale::Mapper
-      attribute :content, Shale::Type::Value
-      attribute :uom, Shale::Type::Value
+    class MeasureList < Lutaml::Model::Serializable
+      attribute :content, :string
+      attribute :uom, :string
 
       xml do
         root "valueList"
diff --git a/lib/ogc/gml/measure_or_nil_reason_list.rb b/lib/ogc/gml/measure_or_nil_reason_list.rb
index b077665..68d8404 100644
--- a/lib/ogc/gml/measure_or_nil_reason_list.rb
+++ b/lib/ogc/gml/measure_or_nil_reason_list.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class MeasureOrNilReasonList < Shale::Mapper
-      attribute :content, Shale::Type::Value
-      attribute :uom, Shale::Type::Value
+    class MeasureOrNilReasonList < Lutaml::Model::Serializable
+      attribute :content, :string
+      attribute :uom, :string
 
       xml do
         root "QuantityList"
diff --git a/lib/ogc/gml/meta_data_property.rb b/lib/ogc/gml/meta_data_property.rb
index 8f709d5..392a436 100644
--- a/lib/ogc/gml/meta_data_property.rb
+++ b/lib/ogc/gml/meta_data_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_meta_data"
 
 module Ogc
   module Gml
-    class MetaDataProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :about, Shale::Type::Value
+    class MetaDataProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :about, :string
       attribute :abstract_meta_data, AbstractMetaData
 
       xml do
diff --git a/lib/ogc/gml/moving_object_status.rb b/lib/ogc/gml/moving_object_status.rb
index a6f2e5f..b84a2e0 100644
--- a/lib/ogc/gml/moving_object_status.rb
+++ b/lib/ogc/gml/moving_object_status.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
diff --git a/lib/ogc/gml/multi_curve.rb b/lib/ogc/gml/multi_curve.rb
index 32d2187..2ddc248 100644
--- a/lib/ogc/gml/multi_curve.rb
+++ b/lib/ogc/gml/multi_curve.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "curve_array_property"
 require_relative "composite_curve"
 
diff --git a/lib/ogc/gml/multi_curve_property.rb b/lib/ogc/gml/multi_curve_property.rb
index 8269293..b9b7507 100644
--- a/lib/ogc/gml/multi_curve_property.rb
+++ b/lib/ogc/gml/multi_curve_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "multi_curve"
 
 module Ogc
   module Gml
-    class MultiCurveProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class MultiCurveProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :multi_curve, MultiCurve
 
       xml do
diff --git a/lib/ogc/gml/multi_geometry.rb b/lib/ogc/gml/multi_geometry.rb
index 203194a..26c3103 100644
--- a/lib/ogc/gml/multi_geometry.rb
+++ b/lib/ogc/gml/multi_geometry.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "geometry_array_property"
 require_relative "geometry_property"
 require_relative "abstract_geometric_aggregate"
diff --git a/lib/ogc/gml/multi_geometry_property.rb b/lib/ogc/gml/multi_geometry_property.rb
index bf85832..54ef608 100644
--- a/lib/ogc/gml/multi_geometry_property.rb
+++ b/lib/ogc/gml/multi_geometry_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_geometric_aggregate"
 
 module Ogc
   module Gml
-    class MultiGeometryProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class MultiGeometryProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :abstract_geometric_aggregate, AbstractGeometricAggregate
 
       xml do
diff --git a/lib/ogc/gml/multi_point.rb b/lib/ogc/gml/multi_point.rb
index abf5c4e..805a817 100644
--- a/lib/ogc/gml/multi_point.rb
+++ b/lib/ogc/gml/multi_point.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "point_array_property"
 require_relative "point_property"
 require_relative "abstract_geometric_aggregate"
diff --git a/lib/ogc/gml/multi_point_property.rb b/lib/ogc/gml/multi_point_property.rb
index 1ba61d5..a29a426 100644
--- a/lib/ogc/gml/multi_point_property.rb
+++ b/lib/ogc/gml/multi_point_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "multi_point"
 
 module Ogc
   module Gml
-    class MultiPointProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class MultiPointProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :multi_point, MultiPoint
 
       xml do
diff --git a/lib/ogc/gml/multi_solid.rb b/lib/ogc/gml/multi_solid.rb
index 8a836e9..1586f43 100644
--- a/lib/ogc/gml/multi_solid.rb
+++ b/lib/ogc/gml/multi_solid.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_geometric_aggregate"
 require_relative "solid_array_property"
 require_relative "solid_property"
diff --git a/lib/ogc/gml/multi_solid_property.rb b/lib/ogc/gml/multi_solid_property.rb
index a3f4e14..4f66b47 100644
--- a/lib/ogc/gml/multi_solid_property.rb
+++ b/lib/ogc/gml/multi_solid_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "multi_solid"
 
 module Ogc
   module Gml
-    class MultiSolidProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class MultiSolidProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :multi_solid, MultiSolid
 
       xml do
diff --git a/lib/ogc/gml/multi_surface.rb b/lib/ogc/gml/multi_surface.rb
index 11f1a7b..2937bf8 100644
--- a/lib/ogc/gml/multi_surface.rb
+++ b/lib/ogc/gml/multi_surface.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_geometric_aggregate"
 require_relative "surface_array_property"
 require_relative "surface_property"
diff --git a/lib/ogc/gml/multi_surface_property.rb b/lib/ogc/gml/multi_surface_property.rb
index 74be7b7..67b4ffa 100644
--- a/lib/ogc/gml/multi_surface_property.rb
+++ b/lib/ogc/gml/multi_surface_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "multi_surface"
 
 module Ogc
   module Gml
-    class MultiSurfaceProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class MultiSurfaceProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :multi_surface, MultiSurface
 
       xml do
diff --git a/lib/ogc/gml/node.rb b/lib/ogc/gml/node.rb
index c96636f..82ed72e 100644
--- a/lib/ogc/gml/node.rb
+++ b/lib/ogc/gml/node.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -12,14 +12,14 @@
 
 module Ogc
   module Gml
-    class DirectedEdgeProperty < Shale::Mapper
+    class DirectedEdgeProperty < Lutaml::Model::Serializable
     end
 
-    class Node < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :aggregation_type, Shale::Type::String
+    class Node < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :aggregation_type, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/node_or_edge_property.rb b/lib/ogc/gml/node_or_edge_property.rb
index 7f85a80..8a3f008 100644
--- a/lib/ogc/gml/node_or_edge_property.rb
+++ b/lib/ogc/gml/node_or_edge_property.rb
@@ -1,19 +1,19 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 # require_relative "edge"
 require_relative "node"
 
 module Ogc
   module Gml
-    class Edge < Shale::Mapper
+    class Edge < Lutaml::Model::Serializable
     end
 
-    class NodeOrEdgeProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class NodeOrEdgeProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :node, Node
       attribute :edge, Edge
 
diff --git a/lib/ogc/gml/node_property.rb b/lib/ogc/gml/node_property.rb
index 396d0ed..6e2a8f8 100644
--- a/lib/ogc/gml/node_property.rb
+++ b/lib/ogc/gml/node_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "node"
 
 module Ogc
   module Gml
-    class NodeProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class NodeProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :node, Node
 
       xml do
diff --git a/lib/ogc/gml/oblique_cartesian_cs.rb b/lib/ogc/gml/oblique_cartesian_cs.rb
index 4b11563..13c147d 100644
--- a/lib/ogc/gml/oblique_cartesian_cs.rb
+++ b/lib/ogc/gml/oblique_cartesian_cs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_system"
 
 module Ogc
diff --git a/lib/ogc/gml/oblique_cartesian_cs_property.rb b/lib/ogc/gml/oblique_cartesian_cs_property.rb
index 2ca3ff7..f48c90f 100644
--- a/lib/ogc/gml/oblique_cartesian_cs_property.rb
+++ b/lib/ogc/gml/oblique_cartesian_cs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "oblique_cartesian_cs"
 
 module Ogc
   module Gml
-    class ObliqueCartesianCSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class ObliqueCartesianCSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :oblique_cartesian_cs, ObliqueCartesianCS
 
       xml do
diff --git a/lib/ogc/gml/observation.rb b/lib/ogc/gml/observation.rb
index 0a156cf..2716c1d 100644
--- a/lib/ogc/gml/observation.rb
+++ b/lib/ogc/gml/observation.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "bounding_shape"
 require_relative "code"
diff --git a/lib/ogc/gml/offset_curve.rb b/lib/ogc/gml/offset_curve.rb
index 7c21e87..abb8d61 100644
--- a/lib/ogc/gml/offset_curve.rb
+++ b/lib/ogc/gml/offset_curve.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "curve_property"
 require_relative "length"
diff --git a/lib/ogc/gml/operation_method.rb b/lib/ogc/gml/operation_method.rb
index fb56db6..1d280a1 100644
--- a/lib/ogc/gml/operation_method.rb
+++ b/lib/ogc/gml/operation_method.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_general_operation_parameter_property"
 require_relative "code"
@@ -13,11 +13,11 @@
 module Ogc
   module Gml
     class OperationMethod < AbstractTopology
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
       attribute :formula_citation, FormulaCitation
       attribute :formula, Code
-      attribute :source_dimensions, Shale::Type::Integer
-      attribute :target_dimensions, Shale::Type::Integer
+      attribute :source_dimensions, :integer
+      attribute :target_dimensions, :integer
       attribute :parameter, AbstractGeneralOperationParameterProperty, collection: true
 
       xml do
diff --git a/lib/ogc/gml/operation_method_property.rb b/lib/ogc/gml/operation_method_property.rb
index 18c508e..e6bc2b9 100644
--- a/lib/ogc/gml/operation_method_property.rb
+++ b/lib/ogc/gml/operation_method_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "operation_method"
 
 module Ogc
   module Gml
-    class OperationMethodProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class OperationMethodProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :operation_method, OperationMethod
 
       xml do
diff --git a/lib/ogc/gml/operation_parameter.rb b/lib/ogc/gml/operation_parameter.rb
index a101f46..d481ed7 100644
--- a/lib/ogc/gml/operation_parameter.rb
+++ b/lib/ogc/gml/operation_parameter.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_general_operation_parameter"
 
 module Ogc
diff --git a/lib/ogc/gml/operation_parameter_group.rb b/lib/ogc/gml/operation_parameter_group.rb
index fab7e05..4792740 100644
--- a/lib/ogc/gml/operation_parameter_group.rb
+++ b/lib/ogc/gml/operation_parameter_group.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_general_operation_parameter_property"
 require_relative "abstract_general_operation_parameter"
 
 module Ogc
   module Gml
     class OperationParameterGroup < AbstractGeneralOperationParameter
-      attribute :maximum_occurs, Shale::Type::Integer
+      attribute :maximum_occurs, :integer
       attribute :parameter, AbstractGeneralOperationParameterProperty, collection: true
 
       xml do
diff --git a/lib/ogc/gml/operation_parameter_group_property.rb b/lib/ogc/gml/operation_parameter_group_property.rb
index 2b2dbd9..c647297 100644
--- a/lib/ogc/gml/operation_parameter_group_property.rb
+++ b/lib/ogc/gml/operation_parameter_group_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "operation_parameter_group"
 
 module Ogc
   module Gml
-    class OperationParameterGroupProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class OperationParameterGroupProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :operation_parameter_group, OperationParameterGroup
 
       xml do
diff --git a/lib/ogc/gml/operation_parameter_property.rb b/lib/ogc/gml/operation_parameter_property.rb
index 15fe06c..98bdbdc 100644
--- a/lib/ogc/gml/operation_parameter_property.rb
+++ b/lib/ogc/gml/operation_parameter_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "operation_parameter"
 
 module Ogc
   module Gml
-    class OperationParameterProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class OperationParameterProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :operation_parameter, OperationParameter
 
       xml do
diff --git a/lib/ogc/gml/operation_property.rb b/lib/ogc/gml/operation_property.rb
index 87431f3..44c8da7 100644
--- a/lib/ogc/gml/operation_property.rb
+++ b/lib/ogc/gml/operation_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_coordinate_operation"
 
 module Ogc
   module Gml
-    class OperationProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class OperationProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_operation, AbstractCoordinateOperation
 
       xml do
diff --git a/lib/ogc/gml/orientable_curve.rb b/lib/ogc/gml/orientable_curve.rb
index 3a15ab8..04a8d53 100644
--- a/lib/ogc/gml/orientable_curve.rb
+++ b/lib/ogc/gml/orientable_curve.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -10,18 +10,18 @@
 
 module Ogc
   module Gml
-    class CurveProperty < Shale::Mapper
+    class CurveProperty < Lutaml::Model::Serializable
     end
 
-    class OrientableCurve < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :srs_name, Shale::Type::Value
-      attribute :srs_dimension, Shale::Type::Integer
-      attribute :axis_labels, Shale::Type::Value
-      attribute :uom_labels, Shale::Type::Value
-      attribute :orientation, Shale::Type::String, default: -> { "+" }
+    class OrientableCurve < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :srs_name, :string
+      attribute :srs_dimension, :integer
+      attribute :axis_labels, :string
+      attribute :uom_labels, :string
+      attribute :orientation, :string, default: -> { "+" }
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/orientable_surface.rb b/lib/ogc/gml/orientable_surface.rb
index 4f935f4..cc88501 100644
--- a/lib/ogc/gml/orientable_surface.rb
+++ b/lib/ogc/gml/orientable_surface.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -10,15 +10,15 @@
 
 module Ogc
   module Gml
-    class OrientableSurface < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :srs_name, Shale::Type::Value
-      attribute :srs_dimension, Shale::Type::Integer
-      attribute :axis_labels, Shale::Type::Value
-      attribute :uom_labels, Shale::Type::Value
-      attribute :orientation, Shale::Type::String, default: -> { "+" }
+    class OrientableSurface < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :srs_name, :string
+      attribute :srs_dimension, :integer
+      attribute :axis_labels, :string
+      attribute :uom_labels, :string
+      attribute :orientation, :string, default: -> { "+" }
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/parameter_value.rb b/lib/ogc/gml/parameter_value.rb
index 7e8b07d..3179c16 100644
--- a/lib/ogc/gml/parameter_value.rb
+++ b/lib/ogc/gml/parameter_value.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "dms_angle"
 require_relative "measure_list"
@@ -9,15 +9,15 @@
 
 module Ogc
   module Gml
-    class ParameterValue < Shale::Mapper
+    class ParameterValue < Lutaml::Model::Serializable
       attribute :value, Measure
       attribute :dms_angle_value, DMSAngle
-      attribute :string_value, Shale::Type::String
-      attribute :integer_value, Shale::Type::Integer
-      attribute :boolean_value, Shale::Type::Boolean
+      attribute :string_value, :string
+      attribute :integer_value, :integer
+      attribute :boolean_value, :boolean
       attribute :value_list, MeasureList
-      attribute :integer_value_list, Shale::Type::Value
-      attribute :value_file, Shale::Type::Value
+      attribute :integer_value_list, :string
+      attribute :value_file, :string
       attribute :operation_parameter, OperationParameterProperty
 
       xml do
diff --git a/lib/ogc/gml/parameter_value_group.rb b/lib/ogc/gml/parameter_value_group.rb
index f6e84bc..bf11068 100644
--- a/lib/ogc/gml/parameter_value_group.rb
+++ b/lib/ogc/gml/parameter_value_group.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_general_parameter_value_property"
 require_relative "reference"
 
 module Ogc
   module Gml
-    class ParameterValueGroup < Shale::Mapper
+    class ParameterValueGroup < Lutaml::Model::Serializable
       attribute :parameter_value, AbstractGeneralParameterValueProperty, collection: true
       attribute :group, Reference
 
diff --git a/lib/ogc/gml/pass_through_operation.rb b/lib/ogc/gml/pass_through_operation.rb
index 9b02239..adc59bb 100644
--- a/lib/ogc/gml/pass_through_operation.rb
+++ b/lib/ogc/gml/pass_through_operation.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -14,7 +14,7 @@
 module Ogc
   module Gml
     class PassThroughOperation < ConcatenatedOperation
-      attribute :modified_coordinate, Shale::Type::Integer, collection: true
+      attribute :modified_coordinate, :integer, collection: true
 
       xml do
         root "PassThroughOperation"
diff --git a/lib/ogc/gml/pass_through_operation_property.rb b/lib/ogc/gml/pass_through_operation_property.rb
index 2c958a2..d1378bc 100644
--- a/lib/ogc/gml/pass_through_operation_property.rb
+++ b/lib/ogc/gml/pass_through_operation_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "pass_through_operation"
 
 module Ogc
   module Gml
-    class PassThroughOperationProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class PassThroughOperationProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :pass_through_operation, PassThroughOperation
 
       xml do
diff --git a/lib/ogc/gml/point.rb b/lib/ogc/gml/point.rb
index 9a72f39..6fc2dd7 100644
--- a/lib/ogc/gml/point.rb
+++ b/lib/ogc/gml/point.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "direct_position"
 require_relative "abstract_geometry"
 
diff --git a/lib/ogc/gml/point_array_property.rb b/lib/ogc/gml/point_array_property.rb
index 6d897d9..3ed7311 100644
--- a/lib/ogc/gml/point_array_property.rb
+++ b/lib/ogc/gml/point_array_property.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "point"
 
 module Ogc
   module Gml
-    class PointArrayProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class PointArrayProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
       attribute :point, Point, collection: true
 
       xml do
diff --git a/lib/ogc/gml/point_property.rb b/lib/ogc/gml/point_property.rb
index 659ef04..cfbd7aa 100644
--- a/lib/ogc/gml/point_property.rb
+++ b/lib/ogc/gml/point_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "point"
 
 module Ogc
   module Gml
-    class PointProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean#, default: -> { "false" }
+    class PointProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean #, default: -> { "false" }
       attribute :point, Point
 
       xml do
diff --git a/lib/ogc/gml/polar_cs.rb b/lib/ogc/gml/polar_cs.rb
index a322c2c..c76e961 100644
--- a/lib/ogc/gml/polar_cs.rb
+++ b/lib/ogc/gml/polar_cs.rb
@@ -1,11 +1,11 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_system"
 
 module Ogc
   module Gml
-    class PolarCS < Shale::Mapper
+    class PolarCS < Lutaml::Model::Serializable
       xml do
         root "PolarCS"
         namespace "http://www.opengis.net/gml/3.2", "gml"
diff --git a/lib/ogc/gml/polar_cs_property.rb b/lib/ogc/gml/polar_cs_property.rb
index 57704f5..8219974 100644
--- a/lib/ogc/gml/polar_cs_property.rb
+++ b/lib/ogc/gml/polar_cs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "polar_cs"
 
 module Ogc
   module Gml
-    class PolarCSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class PolarCSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :polar_cs, PolarCS
 
       xml do
diff --git a/lib/ogc/gml/polygon.rb b/lib/ogc/gml/polygon.rb
index 364a906..ff6754c 100644
--- a/lib/ogc/gml/polygon.rb
+++ b/lib/ogc/gml/polygon.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "reference"
 require_relative "shell_property"
 require_relative "abstract_geometry"
diff --git a/lib/ogc/gml/polygon_patch.rb b/lib/ogc/gml/polygon_patch.rb
index ea9b3a9..6c0de3b 100644
--- a/lib/ogc/gml/polygon_patch.rb
+++ b/lib/ogc/gml/polygon_patch.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "shell_property"
 
 module Ogc
   module Gml
-    class PolygonPatch < Shale::Mapper
-      attribute :interpolation, Shale::Type::String
+    class PolygonPatch < Lutaml::Model::Serializable
+      attribute :interpolation, :string
       attribute :exterior, ShellProperty
       attribute :interior, ShellProperty, collection: true
 
diff --git a/lib/ogc/gml/prime_meridian.rb b/lib/ogc/gml/prime_meridian.rb
index b683e13..f50f81c 100644
--- a/lib/ogc/gml/prime_meridian.rb
+++ b/lib/ogc/gml/prime_meridian.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "angle"
 require_relative "code"
@@ -12,7 +12,7 @@
 module Ogc
   module Gml
     class PrimeMeridian < AbstractTopology
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
       attribute :greenwich_longitude, Angle
 
       xml do
diff --git a/lib/ogc/gml/prime_meridian_property.rb b/lib/ogc/gml/prime_meridian_property.rb
index a800b93..b0bdae4 100644
--- a/lib/ogc/gml/prime_meridian_property.rb
+++ b/lib/ogc/gml/prime_meridian_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "prime_meridian"
 
 module Ogc
   module Gml
-    class PrimeMeridianProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class PrimeMeridianProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :prime_meridian, PrimeMeridian
 
       xml do
diff --git a/lib/ogc/gml/priority_location_property.rb b/lib/ogc/gml/priority_location_property.rb
index 00a41bb..edd3cb0 100644
--- a/lib/ogc/gml/priority_location_property.rb
+++ b/lib/ogc/gml/priority_location_property.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_geometry"
 require_relative "code"
@@ -8,14 +8,14 @@
 
 module Ogc
   module Gml
-    class PriorityLocationProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :priority, Shale::Type::String
+    class PriorityLocationProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :priority, :string
       attribute :abstract_geometry, AbstractGeometry
       attribute :location_key_word, Code
       attribute :location_string, StringOrRef
-      attribute :null, Shale::Type::Value
+      attribute :null, :string
 
       xml do
         root "priorityLocation"
diff --git a/lib/ogc/gml/procedure_property.rb b/lib/ogc/gml/procedure_property.rb
index 727de70..a644b8b 100644
--- a/lib/ogc/gml/procedure_property.rb
+++ b/lib/ogc/gml/procedure_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_feature"
 
 module Ogc
   module Gml
-    class ProcedureProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class ProcedureProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_feature, AbstractFeature
 
       xml do
diff --git a/lib/ogc/gml/projected_crs.rb b/lib/ogc/gml/projected_crs.rb
index ece9892..858f873 100644
--- a/lib/ogc/gml/projected_crs.rb
+++ b/lib/ogc/gml/projected_crs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "cartesian_cs_property"
 require_relative "geodetic_crs_property"
 require_relative "geographic_crs_property"
diff --git a/lib/ogc/gml/projected_crs_property.rb b/lib/ogc/gml/projected_crs_property.rb
index 049201e..b1c5a05 100644
--- a/lib/ogc/gml/projected_crs_property.rb
+++ b/lib/ogc/gml/projected_crs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "projected_crs"
 
 module Ogc
   module Gml
-    class ProjectedCRSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class ProjectedCRSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :projected_crs, ProjectedCRS
 
       xml do
diff --git a/lib/ogc/gml/quantity.rb b/lib/ogc/gml/quantity.rb
index 803b2c0..560c93b 100644
--- a/lib/ogc/gml/quantity.rb
+++ b/lib/ogc/gml/quantity.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "measure"
 
 module Ogc
   module Gml
-    class Quantity < Shale::Mapper
+    class Quantity < Lutaml::Model::Serializable
       attribute :content, Measure
-      attribute :nil_reason, Shale::Type::Value
+      attribute :nil_reason, :string
 
       xml do
         root "Quantity"
diff --git a/lib/ogc/gml/quantity_extent.rb b/lib/ogc/gml/quantity_extent.rb
index 9707dcd..ea942ac 100644
--- a/lib/ogc/gml/quantity_extent.rb
+++ b/lib/ogc/gml/quantity_extent.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "measure_or_nil_reason_list"
 
 module Ogc
   module Gml
-    class QuantityExtent < Shale::Mapper
+    class QuantityExtent < Lutaml::Model::Serializable
       attribute :content, MeasureOrNilReasonList
 
       xml do
diff --git a/lib/ogc/gml/range_set.rb b/lib/ogc/gml/range_set.rb
index 5892eff..de0f6d2 100644
--- a/lib/ogc/gml/range_set.rb
+++ b/lib/ogc/gml/range_set.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "data_block"
 require_relative "file"
@@ -8,9 +8,9 @@
 
 module Ogc
   module Gml
-    class RangeSet < Shale::Mapper
+    class RangeSet < Lutaml::Model::Serializable
       attribute :value_array, ValueArray, collection: true
-      attribute :abstract_scalar_value_list, Shale::Type::Value, collection: true
+      attribute :abstract_scalar_value_list, :string, collection: true
       attribute :data_block, DataBlock
       attribute :file, File
 
diff --git a/lib/ogc/gml/rectangle.rb b/lib/ogc/gml/rectangle.rb
index 106a6f1..4f29d95 100644
--- a/lib/ogc/gml/rectangle.rb
+++ b/lib/ogc/gml/rectangle.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "shell_property"
 
 module Ogc
   module Gml
-    class Rectangle < Shale::Mapper
-      attribute :interpolation, Shale::Type::String
+    class Rectangle < Lutaml::Model::Serializable
+      attribute :interpolation, :string
       attribute :exterior, ShellProperty
 
       xml do
diff --git a/lib/ogc/gml/rectified_grid.rb b/lib/ogc/gml/rectified_grid.rb
index 0010e62..b925d8c 100644
--- a/lib/ogc/gml/rectified_grid.rb
+++ b/lib/ogc/gml/rectified_grid.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -12,20 +12,20 @@
 
 module Ogc
   module Gml
-    class RectifiedGrid < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :srs_name, Shale::Type::Value
-      attribute :srs_dimension, Shale::Type::Integer
-      attribute :axis_labels, Shale::Type::Value
-      attribute :uom_labels, Shale::Type::Value
-      attribute :dimension, Shale::Type::Integer
+    class RectifiedGrid < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :srs_name, :string
+      attribute :srs_dimension, :integer
+      attribute :axis_labels, :string
+      attribute :uom_labels, :string
+      attribute :dimension, :integer
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
       attribute :limits, GridLimits
-      attribute :axis_name, Shale::Type::String, collection: true
+      attribute :axis_name, :string, collection: true
       attribute :origin, PointProperty
       attribute :offset_vector, Vector, collection: true
 
diff --git a/lib/ogc/gml/ref_location.rb b/lib/ogc/gml/ref_location.rb
index 0b31a73..8b0c4f2 100644
--- a/lib/ogc/gml/ref_location.rb
+++ b/lib/ogc/gml/ref_location.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "affine_placement"
 
 module Ogc
   module Gml
-    class RefLocation < Shale::Mapper
+    class RefLocation < Lutaml::Model::Serializable
       attribute :affine_placement, AffinePlacement
 
       xml do
diff --git a/lib/ogc/gml/reference.rb b/lib/ogc/gml/reference.rb
index b8aaa17..9d22f62 100644
--- a/lib/ogc/gml/reference.rb
+++ b/lib/ogc/gml/reference.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class Reference < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class Reference < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
 
       xml do
         root "statusReference"
diff --git a/lib/ogc/gml/related_time.rb b/lib/ogc/gml/related_time.rb
index 8687da2..023921f 100644
--- a/lib/ogc/gml/related_time.rb
+++ b/lib/ogc/gml/related_time.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_time_primitive"
 
 module Ogc
   module Gml
-    class RelatedTime < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :relative_position, Shale::Type::String
+    class RelatedTime < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
+      attribute :relative_position, :string
       attribute :abstract_time_primitive, AbstractTimePrimitive
 
       xml do
diff --git a/lib/ogc/gml/result.rb b/lib/ogc/gml/result.rb
index cd60fcd..e5aec08 100644
--- a/lib/ogc/gml/result.rb
+++ b/lib/ogc/gml/result.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class Result < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class Result < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
 
       xml do
         root "resultOf"
diff --git a/lib/ogc/gml/ring.rb b/lib/ogc/gml/ring.rb
index e81a379..0fc0f2b 100644
--- a/lib/ogc/gml/ring.rb
+++ b/lib/ogc/gml/ring.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "composite_curve"
 
 module Ogc
   module Gml
     class Ring < CompositeCurve
-      attribute :aggregation_type, Shale::Type::String
+      attribute :aggregation_type, :string
 
       xml do
         root "Ring"
diff --git a/lib/ogc/gml/second_defining_parameter1.rb b/lib/ogc/gml/second_defining_parameter1.rb
index f6cb7ba..fcb2574 100644
--- a/lib/ogc/gml/second_defining_parameter1.rb
+++ b/lib/ogc/gml/second_defining_parameter1.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "second_defining_parameter2"
 
 module Ogc
   module Gml
-    class SecondDefiningParameter1 < Shale::Mapper
+    class SecondDefiningParameter1 < Lutaml::Model::Serializable
       attribute :second_defining_parameter, SecondDefiningParameter2
 
       xml do
diff --git a/lib/ogc/gml/second_defining_parameter2.rb b/lib/ogc/gml/second_defining_parameter2.rb
index 20342cc..f103266 100644
--- a/lib/ogc/gml/second_defining_parameter2.rb
+++ b/lib/ogc/gml/second_defining_parameter2.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "length"
 require_relative "measure"
 
 module Ogc
   module Gml
-    class SecondDefiningParameter2 < Shale::Mapper
+    class SecondDefiningParameter2 < Lutaml::Model::Serializable
       attribute :inverse_flattening, Measure
       attribute :semi_minor_axis, Length
-      attribute :is_sphere, Shale::Type::Boolean, default: -> { "true" }
+      attribute :is_sphere, :boolean, default: -> { true }
 
       xml do
         root "SecondDefiningParameter"
diff --git a/lib/ogc/gml/sequence_rule.rb b/lib/ogc/gml/sequence_rule.rb
index c4439c3..d8c379e 100644
--- a/lib/ogc/gml/sequence_rule.rb
+++ b/lib/ogc/gml/sequence_rule.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class SequenceRule < Shale::Mapper
-      attribute :content, Shale::Type::String
-      attribute :order, Shale::Type::String
-      attribute :axis_order, Shale::Type::Value
+    class SequenceRule < Lutaml::Model::Serializable
+      attribute :content, :string
+      attribute :order, :string
+      attribute :axis_order, :string
 
       xml do
         root "SequenceRuleType"
diff --git a/lib/ogc/gml/shell.rb b/lib/ogc/gml/shell.rb
index ad3cbeb..5f7f4c1 100644
--- a/lib/ogc/gml/shell.rb
+++ b/lib/ogc/gml/shell.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "surface_property"
 
 module Ogc
   module Gml
-    class SurfaceProperty < Shale::Mapper
+    class SurfaceProperty < Lutaml::Model::Serializable
     end
 
-    class Shell < Shale::Mapper
-      attribute :aggregation_type, Shale::Type::String
+    class Shell < Lutaml::Model::Serializable
+      attribute :aggregation_type, :string
       attribute :surface_member, SurfaceProperty, collection: true
 
       xml do
diff --git a/lib/ogc/gml/shell_property.rb b/lib/ogc/gml/shell_property.rb
index 0ff989d..dfc4fbb 100644
--- a/lib/ogc/gml/shell_property.rb
+++ b/lib/ogc/gml/shell_property.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "shell"
 require_relative "ring"
@@ -8,7 +8,7 @@
 
 module Ogc
   module Gml
-    class ShellProperty < Shale::Mapper
+    class ShellProperty < Lutaml::Model::Serializable
       attribute :shell, Shell
       attribute :ring, Ring
       attribute :linear_ring, LinearRing
diff --git a/lib/ogc/gml/single_crs_property.rb b/lib/ogc/gml/single_crs_property.rb
index 7d63bfa..da15f8e 100644
--- a/lib/ogc/gml/single_crs_property.rb
+++ b/lib/ogc/gml/single_crs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_crs"
 
 module Ogc
   module Gml
-    class SingleCRSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class SingleCRSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_single_crs, AbstractCRS
 
       xml do
diff --git a/lib/ogc/gml/single_operation_property.rb b/lib/ogc/gml/single_operation_property.rb
index 5c84002..81d5ed0 100644
--- a/lib/ogc/gml/single_operation_property.rb
+++ b/lib/ogc/gml/single_operation_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_coordinate_operation"
 
 module Ogc
   module Gml
-    class SingleOperationProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class SingleOperationProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_single_operation, AbstractCoordinateOperation
 
       xml do
diff --git a/lib/ogc/gml/solid.rb b/lib/ogc/gml/solid.rb
index d21e7fd..14c6e26 100644
--- a/lib/ogc/gml/solid.rb
+++ b/lib/ogc/gml/solid.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_solid"
 require_relative "shell_property"
 
diff --git a/lib/ogc/gml/solid_array_property.rb b/lib/ogc/gml/solid_array_property.rb
index affab41..00e87b0 100644
--- a/lib/ogc/gml/solid_array_property.rb
+++ b/lib/ogc/gml/solid_array_property.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_solid"
 
 module Ogc
   module Gml
-    class SolidArrayProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class SolidArrayProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
       attribute :abstract_solid, AbstractSolid, collection: true
 
       xml do
diff --git a/lib/ogc/gml/solid_property.rb b/lib/ogc/gml/solid_property.rb
index ed52ec9..d1098a1 100644
--- a/lib/ogc/gml/solid_property.rb
+++ b/lib/ogc/gml/solid_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_solid"
 
 module Ogc
   module Gml
-    class SolidProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class SolidProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :abstract_solid, AbstractSolid
 
       xml do
diff --git a/lib/ogc/gml/sphere.rb b/lib/ogc/gml/sphere.rb
index 4e1033c..3626e43 100644
--- a/lib/ogc/gml/sphere.rb
+++ b/lib/ogc/gml/sphere.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "cylinder"
 
 module Ogc
diff --git a/lib/ogc/gml/spherical_cs.rb b/lib/ogc/gml/spherical_cs.rb
index d84cfd1..0d5fa96 100644
--- a/lib/ogc/gml/spherical_cs.rb
+++ b/lib/ogc/gml/spherical_cs.rb
@@ -1,11 +1,11 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_system"
 
 module Ogc
   module Gml
-    class SphericalCS < Shale::Mapper
+    class SphericalCS < Lutaml::Model::Serializable
       xml do
         root "SphericalCS"
         namespace "http://www.opengis.net/gml/3.2", "gml"
diff --git a/lib/ogc/gml/spherical_cs_property.rb b/lib/ogc/gml/spherical_cs_property.rb
index 617c6f6..bcaeb88 100644
--- a/lib/ogc/gml/spherical_cs_property.rb
+++ b/lib/ogc/gml/spherical_cs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "spherical_cs"
 
 module Ogc
   module Gml
-    class SphericalCSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class SphericalCSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :spherical_cs, SphericalCS
 
       xml do
diff --git a/lib/ogc/gml/string_or_ref.rb b/lib/ogc/gml/string_or_ref.rb
index 15af3a4..cb783ef 100644
--- a/lib/ogc/gml/string_or_ref.rb
+++ b/lib/ogc/gml/string_or_ref.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class StringOrRef < Shale::Mapper
-      attribute :content, Shale::Type::String
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class StringOrRef < Lutaml::Model::Serializable
+      attribute :content, :string
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
 
       xml do
         root "status"
diff --git a/lib/ogc/gml/surface.rb b/lib/ogc/gml/surface.rb
index 94beabd..ce7a2d9 100644
--- a/lib/ogc/gml/surface.rb
+++ b/lib/ogc/gml/surface.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_surface"
 require_relative "surface_patch_array_property"
 
diff --git a/lib/ogc/gml/surface_array_property.rb b/lib/ogc/gml/surface_array_property.rb
index 102c706..117294e 100644
--- a/lib/ogc/gml/surface_array_property.rb
+++ b/lib/ogc/gml/surface_array_property.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_surface"
 
 module Ogc
   module Gml
-    class SurfaceArrayProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class SurfaceArrayProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
       attribute :abstract_surface, AbstractSurface, collection: true
 
       xml do
diff --git a/lib/ogc/gml/surface_patch_array_property.rb b/lib/ogc/gml/surface_patch_array_property.rb
index 16ec180..2e75183 100644
--- a/lib/ogc/gml/surface_patch_array_property.rb
+++ b/lib/ogc/gml/surface_patch_array_property.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_surface_patch"
 require_relative "triangle"
 
 module Ogc
   module Gml
-    class SurfacePatchArrayProperty < Shale::Mapper
+    class SurfacePatchArrayProperty < Lutaml::Model::Serializable
       attribute :abstract_surface_patch, AbstractSurfacePatch, collection: true
       attribute :polygon_patch, PolygonPatch, collection: true
       attribute :rectangle, Rectangle, collection: true
diff --git a/lib/ogc/gml/surface_property.rb b/lib/ogc/gml/surface_property.rb
index eb82f82..d17be6a 100644
--- a/lib/ogc/gml/surface_property.rb
+++ b/lib/ogc/gml/surface_property.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_surface"
 require_relative "polygon"
 
 module Ogc
   module Gml
-    class SurfaceProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean#, default: -> { "false" }
+    class SurfaceProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean #, default: -> { "false" }
       attribute :abstract_surface, AbstractSurface
       attribute :polygon, Polygon
 
diff --git a/lib/ogc/gml/target_property.rb b/lib/ogc/gml/target_property.rb
index b108ecb..b4214ba 100644
--- a/lib/ogc/gml/target_property.rb
+++ b/lib/ogc/gml/target_property.rb
@@ -1,16 +1,16 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_feature"
 require_relative "abstract_geometry"
 
 module Ogc
   module Gml
-    class TargetProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class TargetProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :abstract_feature, AbstractFeature
       attribute :abstract_geometry, AbstractGeometry
 
diff --git a/lib/ogc/gml/temporal_crs.rb b/lib/ogc/gml/temporal_crs.rb
index 8b128a6..07752a5 100644
--- a/lib/ogc/gml/temporal_crs.rb
+++ b/lib/ogc/gml/temporal_crs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "temporal_cs_property"
 require_relative "temporal_datum_property"
 require_relative "time_cs_property"
diff --git a/lib/ogc/gml/temporal_crs_property.rb b/lib/ogc/gml/temporal_crs_property.rb
index 36571e1..0e266c2 100644
--- a/lib/ogc/gml/temporal_crs_property.rb
+++ b/lib/ogc/gml/temporal_crs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "temporal_crs"
 
 module Ogc
   module Gml
-    class TemporalCRSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class TemporalCRSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :temporal_crs, TemporalCRS
 
       xml do
diff --git a/lib/ogc/gml/temporal_cs.rb b/lib/ogc/gml/temporal_cs.rb
index fe233b8..c3d46c3 100644
--- a/lib/ogc/gml/temporal_cs.rb
+++ b/lib/ogc/gml/temporal_cs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_system"
 
 module Ogc
diff --git a/lib/ogc/gml/temporal_cs_property.rb b/lib/ogc/gml/temporal_cs_property.rb
index 90f7073..f992977 100644
--- a/lib/ogc/gml/temporal_cs_property.rb
+++ b/lib/ogc/gml/temporal_cs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "temporal_cs"
 
 module Ogc
   module Gml
-    class TemporalCSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class TemporalCSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :temporal_cs, TemporalCS
 
       xml do
diff --git a/lib/ogc/gml/temporal_datum.rb b/lib/ogc/gml/temporal_datum.rb
index aa738aa..6e4d2e5 100644
--- a/lib/ogc/gml/temporal_datum.rb
+++ b/lib/ogc/gml/temporal_datum.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -12,9 +12,9 @@
 module Ogc
   module Gml
     class TemporalDatum < AbstractTopology
-      attribute :remarks, Shale::Type::String
-      attribute :domain_of_validity, Shale::Type::String
-      attribute :scope, Shale::Type::String, collection: true
+      attribute :remarks, :string
+      attribute :domain_of_validity, :string
+      attribute :scope, :string, collection: true
       attribute :origin, TimeInstantProperty
 
       xml do
diff --git a/lib/ogc/gml/temporal_datum_property.rb b/lib/ogc/gml/temporal_datum_property.rb
index d77b66b..513b8b0 100644
--- a/lib/ogc/gml/temporal_datum_property.rb
+++ b/lib/ogc/gml/temporal_datum_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "temporal_datum"
 
 module Ogc
   module Gml
-    class TemporalDatumProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class TemporalDatumProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :temporal_datum, TemporalDatum
 
       xml do
diff --git a/lib/ogc/gml/time_calendar.rb b/lib/ogc/gml/time_calendar.rb
index bf589f0..1eb03e4 100644
--- a/lib/ogc/gml/time_calendar.rb
+++ b/lib/ogc/gml/time_calendar.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -12,8 +12,8 @@
 module Ogc
   module Gml
     class TimeCalendar < AbstractTopology
-      attribute :remarks, Shale::Type::String
-      attribute :domain_of_validity, Shale::Type::String
+      attribute :remarks, :string
+      attribute :domain_of_validity, :string
       attribute :reference_frame, TimeCalendarEraProperty, collection: true
 
       xml do
diff --git a/lib/ogc/gml/time_calendar_era.rb b/lib/ogc/gml/time_calendar_era.rb
index f4e93b8..26fd977 100644
--- a/lib/ogc/gml/time_calendar_era.rb
+++ b/lib/ogc/gml/time_calendar_era.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -13,10 +13,10 @@
 module Ogc
   module Gml
     class TimeCalendarEra < AbstractTopology
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
       attribute :reference_event, StringOrRef
-      attribute :reference_date, Shale::Type::Value
-      attribute :julian_reference, Shale::Type::Float
+      attribute :reference_date, :string
+      attribute :julian_reference, :float
       attribute :epoch_of_use, TimePeriodProperty
 
       xml do
diff --git a/lib/ogc/gml/time_calendar_era_property.rb b/lib/ogc/gml/time_calendar_era_property.rb
index c842847..9ac4f95 100644
--- a/lib/ogc/gml/time_calendar_era_property.rb
+++ b/lib/ogc/gml/time_calendar_era_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "time_calendar_era"
 
 module Ogc
   module Gml
-    class TimeCalendarEraProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class TimeCalendarEraProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :time_calendar_era, TimeCalendarEra
 
       xml do
diff --git a/lib/ogc/gml/time_calendar_property.rb b/lib/ogc/gml/time_calendar_property.rb
index 1368567..8e4c968 100644
--- a/lib/ogc/gml/time_calendar_property.rb
+++ b/lib/ogc/gml/time_calendar_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "time_calendar"
 
 module Ogc
   module Gml
-    class TimeCalendarProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class TimeCalendarProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :time_calendar, TimeCalendar
 
       xml do
diff --git a/lib/ogc/gml/time_clock.rb b/lib/ogc/gml/time_clock.rb
index 3ac0e15..7df1a10 100644
--- a/lib/ogc/gml/time_clock.rb
+++ b/lib/ogc/gml/time_clock.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -13,11 +13,11 @@
 module Ogc
   module Gml
     class TimeClock < AbstractTopology
-      attribute :remarks, Shale::Type::String
-      attribute :domain_of_validity, Shale::Type::String
+      attribute :remarks, :string
+      attribute :domain_of_validity, :string
       attribute :reference_event, StringOrRef
-      attribute :reference_time, Shale::Type::Value
-      attribute :utc_reference, Shale::Type::Value
+      attribute :reference_time, :string
+      attribute :utc_reference, :string
       attribute :date_basis, TimeCalendarProperty, collection: true
 
       xml do
diff --git a/lib/ogc/gml/time_coordinate_system.rb b/lib/ogc/gml/time_coordinate_system.rb
index 7c06556..a45917d 100644
--- a/lib/ogc/gml/time_coordinate_system.rb
+++ b/lib/ogc/gml/time_coordinate_system.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -14,8 +14,8 @@
 module Ogc
   module Gml
     class TimeCoordinateSystem < AbstractTopology
-      attribute :remarks, Shale::Type::String
-      attribute :domain_of_validity, Shale::Type::String
+      attribute :remarks, :string
+      attribute :domain_of_validity, :string
       attribute :origin_position, TimePosition
       attribute :origin, TimeInstantProperty
       attribute :interval, TimeIntervalLength
diff --git a/lib/ogc/gml/time_cs.rb b/lib/ogc/gml/time_cs.rb
index 628a261..04a0a0a 100644
--- a/lib/ogc/gml/time_cs.rb
+++ b/lib/ogc/gml/time_cs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_system"
 
 module Ogc
diff --git a/lib/ogc/gml/time_cs_property.rb b/lib/ogc/gml/time_cs_property.rb
index fe9c830..58c6777 100644
--- a/lib/ogc/gml/time_cs_property.rb
+++ b/lib/ogc/gml/time_cs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "time_cs"
 
 module Ogc
   module Gml
-    class TimeCSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class TimeCSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :time_cs, TimeCS
 
       xml do
diff --git a/lib/ogc/gml/time_edge.rb b/lib/ogc/gml/time_edge.rb
index 5ac275d..c718b6c 100644
--- a/lib/ogc/gml/time_edge.rb
+++ b/lib/ogc/gml/time_edge.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
diff --git a/lib/ogc/gml/time_edge_property.rb b/lib/ogc/gml/time_edge_property.rb
index ac3619c..321efd8 100644
--- a/lib/ogc/gml/time_edge_property.rb
+++ b/lib/ogc/gml/time_edge_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "time_edge"
 
 module Ogc
   module Gml
-    class TimeEdgeProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TimeEdgeProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :time_edge, TimeEdge
 
       xml do
diff --git a/lib/ogc/gml/time_instant.rb b/lib/ogc/gml/time_instant.rb
index 2c8e8b3..89d610f 100644
--- a/lib/ogc/gml/time_instant.rb
+++ b/lib/ogc/gml/time_instant.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_time_geometric_primitive"
 require_relative "time_position"
 
diff --git a/lib/ogc/gml/time_instant_property.rb b/lib/ogc/gml/time_instant_property.rb
index 09a57f4..dcbfa97 100644
--- a/lib/ogc/gml/time_instant_property.rb
+++ b/lib/ogc/gml/time_instant_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "time_instant"
 
 module Ogc
   module Gml
-    class TimeInstantProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TimeInstantProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :time_instant, TimeInstant
 
       xml do
diff --git a/lib/ogc/gml/time_interval_length.rb b/lib/ogc/gml/time_interval_length.rb
index 001518b..d8843e8 100644
--- a/lib/ogc/gml/time_interval_length.rb
+++ b/lib/ogc/gml/time_interval_length.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class TimeIntervalLength < Shale::Mapper
-      attribute :content, Shale::Type::Float
-      attribute :unit, Shale::Type::String
-      attribute :radix, Shale::Type::Integer
-      attribute :factor, Shale::Type::Integer
+    class TimeIntervalLength < Lutaml::Model::Serializable
+      attribute :content, :float
+      attribute :unit, :string
+      attribute :radix, :integer
+      attribute :factor, :integer
 
       xml do
         root "timeInterval"
diff --git a/lib/ogc/gml/time_node.rb b/lib/ogc/gml/time_node.rb
index 7926bd0..e699041 100644
--- a/lib/ogc/gml/time_node.rb
+++ b/lib/ogc/gml/time_node.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 # require_relative "time_edge_property"
 require_relative "time_instant_property"
 require_relative "abstract_time_topology_primitive"
 
 module Ogc
   module Gml
-    class TimeEdgeProperty < Shale::Mapper
+    class TimeEdgeProperty < Lutaml::Model::Serializable
     end
 
     class TimeNode < AbstractTimeTopologyPrimitive
diff --git a/lib/ogc/gml/time_node_property.rb b/lib/ogc/gml/time_node_property.rb
index 3ca2a4f..f196659 100644
--- a/lib/ogc/gml/time_node_property.rb
+++ b/lib/ogc/gml/time_node_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "time_node"
 
 module Ogc
   module Gml
-    class TimeNodeProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TimeNodeProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :time_node, TimeNode
 
       xml do
diff --git a/lib/ogc/gml/time_ordinal_era.rb b/lib/ogc/gml/time_ordinal_era.rb
index b4d4e2c..807767c 100644
--- a/lib/ogc/gml/time_ordinal_era.rb
+++ b/lib/ogc/gml/time_ordinal_era.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "reference"
 require_relative "related_time"
 require_relative "time_node_property"
@@ -10,11 +10,11 @@
 
 module Ogc
   module Gml
-    class TimeOrdinalEraProperty < Shale::Mapper
+    class TimeOrdinalEraProperty < Lutaml::Model::Serializable
     end
 
     class TimeOrdinalEra < AbstractTopology
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
       attribute :related_time, RelatedTime, collection: true
       attribute :start, TimeNodeProperty
       attribute :end, TimeNodeProperty
diff --git a/lib/ogc/gml/time_ordinal_era_property.rb b/lib/ogc/gml/time_ordinal_era_property.rb
index 13dce6f..41c988e 100644
--- a/lib/ogc/gml/time_ordinal_era_property.rb
+++ b/lib/ogc/gml/time_ordinal_era_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "time_ordinal_era"
 
 module Ogc
   module Gml
-    class TimeOrdinalEraProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class TimeOrdinalEraProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :time_ordinal_era, TimeOrdinalEra
 
       xml do
diff --git a/lib/ogc/gml/time_ordinal_reference_system.rb b/lib/ogc/gml/time_ordinal_reference_system.rb
index 2a53b19..e16dfe2 100644
--- a/lib/ogc/gml/time_ordinal_reference_system.rb
+++ b/lib/ogc/gml/time_ordinal_reference_system.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -12,8 +12,8 @@
 module Ogc
   module Gml
     class TimeOrdinalReferenceSystem < AbstractTopology
-      attribute :remarks, Shale::Type::String
-      attribute :domain_of_validity, Shale::Type::String
+      attribute :remarks, :string
+      attribute :domain_of_validity, :string
       attribute :component, TimeOrdinalEraProperty, collection: true
 
       xml do
diff --git a/lib/ogc/gml/time_period.rb b/lib/ogc/gml/time_period.rb
index b99fa51..8ff14ef 100644
--- a/lib/ogc/gml/time_period.rb
+++ b/lib/ogc/gml/time_period.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "time_instant_property"
 require_relative "time_interval_length"
 require_relative "time_position"
@@ -13,7 +13,7 @@ class TimePeriod < AbstractTimeGeometricPrimitive
       attribute :begin, TimeInstantProperty
       attribute :end_position, TimePosition
       attribute :end, TimeInstantProperty
-      attribute :duration, Shale::Type::Value
+      attribute :duration, :string
       attribute :time_interval, TimeIntervalLength
 
       xml do
diff --git a/lib/ogc/gml/time_period_property.rb b/lib/ogc/gml/time_period_property.rb
index c329b39..4890f51 100644
--- a/lib/ogc/gml/time_period_property.rb
+++ b/lib/ogc/gml/time_period_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "time_period"
 
 module Ogc
   module Gml
-    class TimePeriodProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TimePeriodProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :time_period, TimePeriod
 
       xml do
diff --git a/lib/ogc/gml/time_position.rb b/lib/ogc/gml/time_position.rb
index 1f32d33..d7c9ee6 100644
--- a/lib/ogc/gml/time_position.rb
+++ b/lib/ogc/gml/time_position.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class TimePosition < Shale::Mapper
-      attribute :content, Shale::Type::Value
-      attribute :frame, Shale::Type::Value, default: -> { "#ISO-8601" }
-      attribute :calendar_era_name, Shale::Type::String
-      attribute :indeterminate_position, Shale::Type::String
+    class TimePosition < Lutaml::Model::Serializable
+      attribute :content, :string
+      attribute :frame, :string, default: -> { "#ISO-8601" }
+      attribute :calendar_era_name, :string
+      attribute :indeterminate_position, :string
 
       xml do
         root "timePosition"
diff --git a/lib/ogc/gml/time_primitive_property.rb b/lib/ogc/gml/time_primitive_property.rb
index e7eb326..c689faa 100644
--- a/lib/ogc/gml/time_primitive_property.rb
+++ b/lib/ogc/gml/time_primitive_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_time_primitive"
 
 module Ogc
   module Gml
-    class TimePrimitiveProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TimePrimitiveProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :abstract_time_primitive, AbstractTimePrimitive
 
       xml do
diff --git a/lib/ogc/gml/time_reference_system.rb b/lib/ogc/gml/time_reference_system.rb
index 70cc535..f74d618 100644
--- a/lib/ogc/gml/time_reference_system.rb
+++ b/lib/ogc/gml/time_reference_system.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -11,8 +11,8 @@
 module Ogc
   module Gml
     class TimeReferenceSystem < AbstractTopology
-      attribute :remarks, Shale::Type::String
-      attribute :domain_of_validity, Shale::Type::String
+      attribute :remarks, :string
+      attribute :domain_of_validity, :string
 
       xml do
         root "TimeReferenceSystem"
diff --git a/lib/ogc/gml/time_topology_complex.rb b/lib/ogc/gml/time_topology_complex.rb
index c5e8cf8..987cc1c 100644
--- a/lib/ogc/gml/time_topology_complex.rb
+++ b/lib/ogc/gml/time_topology_complex.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
diff --git a/lib/ogc/gml/time_topology_primitive_property.rb b/lib/ogc/gml/time_topology_primitive_property.rb
index ef51588..5100fe7 100644
--- a/lib/ogc/gml/time_topology_primitive_property.rb
+++ b/lib/ogc/gml/time_topology_primitive_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_time_topology_primitive"
 
 module Ogc
   module Gml
-    class TimeTopologyPrimitiveProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TimeTopologyPrimitiveProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :abstract_time_topology_primitive, AbstractTimeTopologyPrimitive
 
       xml do
diff --git a/lib/ogc/gml/tin.rb b/lib/ogc/gml/tin.rb
index bc7ea20..65b9c4a 100644
--- a/lib/ogc/gml/tin.rb
+++ b/lib/ogc/gml/tin.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "control_point"
 require_relative "length"
diff --git a/lib/ogc/gml/topo_complex.rb b/lib/ogc/gml/topo_complex.rb
index cc569bc..0144a5e 100644
--- a/lib/ogc/gml/topo_complex.rb
+++ b/lib/ogc/gml/topo_complex.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -12,15 +12,15 @@
 
 module Ogc
   module Gml
-    class TopoComplexProperty < Shale::Mapper
+    class TopoComplexProperty < Lutaml::Model::Serializable
     end
 
-    class TopoComplex < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :is_maximal, Shale::Type::Boolean, default: -> { "false" }
-      attribute :aggregation_type, Shale::Type::String
+    class TopoComplex < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :is_maximal, :boolean, default: -> { false }
+      attribute :aggregation_type, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/topo_complex_property.rb b/lib/ogc/gml/topo_complex_property.rb
index b1a4b0f..8f01861 100644
--- a/lib/ogc/gml/topo_complex_property.rb
+++ b/lib/ogc/gml/topo_complex_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "topo_complex"
 
 module Ogc
   module Gml
-    class TopoComplexProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class TopoComplexProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :topo_complex, TopoComplex
 
       xml do
diff --git a/lib/ogc/gml/topo_curve.rb b/lib/ogc/gml/topo_curve.rb
index 9eb0d30..32d0237 100644
--- a/lib/ogc/gml/topo_curve.rb
+++ b/lib/ogc/gml/topo_curve.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -10,11 +10,11 @@
 
 module Ogc
   module Gml
-    class TopoCurve < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :aggregation_type, Shale::Type::String
+    class TopoCurve < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :aggregation_type, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/topo_curve_property.rb b/lib/ogc/gml/topo_curve_property.rb
index a638927..4f772d6 100644
--- a/lib/ogc/gml/topo_curve_property.rb
+++ b/lib/ogc/gml/topo_curve_property.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "topo_curve"
 
 module Ogc
   module Gml
-    class TopoCurveProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TopoCurveProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
       attribute :topo_curve, TopoCurve
 
       xml do
diff --git a/lib/ogc/gml/topo_point.rb b/lib/ogc/gml/topo_point.rb
index 7193a7b..fb0ad86 100644
--- a/lib/ogc/gml/topo_point.rb
+++ b/lib/ogc/gml/topo_point.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
diff --git a/lib/ogc/gml/topo_point_property.rb b/lib/ogc/gml/topo_point_property.rb
index 3466a4f..f8b6689 100644
--- a/lib/ogc/gml/topo_point_property.rb
+++ b/lib/ogc/gml/topo_point_property.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "topo_point"
 
 module Ogc
   module Gml
-    class TopoPointProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TopoPointProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
       attribute :topo_point, TopoPoint
 
       xml do
diff --git a/lib/ogc/gml/topo_primitive_array_association.rb b/lib/ogc/gml/topo_primitive_array_association.rb
index a6f917f..72d84a2 100644
--- a/lib/ogc/gml/topo_primitive_array_association.rb
+++ b/lib/ogc/gml/topo_primitive_array_association.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_topo_primitive"
 
 module Ogc
   module Gml
-    class TopoPrimitiveArrayAssociation < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TopoPrimitiveArrayAssociation < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
       attribute :abstract_topo_primitive, AbstractTopoPrimitive, collection: true
 
       xml do
diff --git a/lib/ogc/gml/topo_primitive_member.rb b/lib/ogc/gml/topo_primitive_member.rb
index 1ba0f86..26ffbac 100644
--- a/lib/ogc/gml/topo_primitive_member.rb
+++ b/lib/ogc/gml/topo_primitive_member.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_topo_primitive"
 
 module Ogc
   module Gml
-    class TopoPrimitiveMember < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TopoPrimitiveMember < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :abstract_topo_primitive, AbstractTopoPrimitive
 
       xml do
diff --git a/lib/ogc/gml/topo_solid.rb b/lib/ogc/gml/topo_solid.rb
index 33d4c56..3abc711 100644
--- a/lib/ogc/gml/topo_solid.rb
+++ b/lib/ogc/gml/topo_solid.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -12,15 +12,15 @@
 
 module Ogc
   module Gml
-    class DirectedFaceProperty < Shale::Mapper
+    class DirectedFaceProperty < Lutaml::Model::Serializable
     end
 
-    class TopoSolid < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :aggregation_type, Shale::Type::String
-      attribute :universal, Shale::Type::Boolean, default: -> { "false" }
+    class TopoSolid < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :aggregation_type, :string
+      attribute :universal, :boolean, default: -> { false }
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/topo_solid_property.rb b/lib/ogc/gml/topo_solid_property.rb
index 1b6d51d..21d1c76 100644
--- a/lib/ogc/gml/topo_solid_property.rb
+++ b/lib/ogc/gml/topo_solid_property.rb
@@ -1,15 +1,15 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "topo_solid"
 
 module Ogc
   module Gml
-    class TopoSolidProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TopoSolidProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
       attribute :topo_solid, TopoSolid
 
       xml do
diff --git a/lib/ogc/gml/topo_surface.rb b/lib/ogc/gml/topo_surface.rb
index 02a97c5..12cd655 100644
--- a/lib/ogc/gml/topo_surface.rb
+++ b/lib/ogc/gml/topo_surface.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -10,11 +10,11 @@
 
 module Ogc
   module Gml
-    class TopoSurface < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :aggregation_type, Shale::Type::String
+    class TopoSurface < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :aggregation_type, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/topo_surface_property.rb b/lib/ogc/gml/topo_surface_property.rb
index 0003edb..b38276f 100644
--- a/lib/ogc/gml/topo_surface_property.rb
+++ b/lib/ogc/gml/topo_surface_property.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "topo_surface"
 
 module Ogc
   module Gml
-    class TopoSurfaceProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TopoSurfaceProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
       attribute :topo_surface, TopoSurface
 
       xml do
diff --git a/lib/ogc/gml/topo_volume.rb b/lib/ogc/gml/topo_volume.rb
index 6cc7141..134deb9 100644
--- a/lib/ogc/gml/topo_volume.rb
+++ b/lib/ogc/gml/topo_volume.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -10,11 +10,11 @@
 
 module Ogc
   module Gml
-    class TopoVolume < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :aggregation_type, Shale::Type::String
+    class TopoVolume < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :aggregation_type, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/topo_volume_property.rb b/lib/ogc/gml/topo_volume_property.rb
index 7580949..efe085a 100644
--- a/lib/ogc/gml/topo_volume_property.rb
+++ b/lib/ogc/gml/topo_volume_property.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "topo_volume"
 
 module Ogc
   module Gml
-    class TopoVolumeProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
+    class TopoVolumeProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
       attribute :topo_volume, TopoVolume
 
       xml do
diff --git a/lib/ogc/gml/transformation.rb b/lib/ogc/gml/transformation.rb
index 7ed4fad..41faafc 100644
--- a/lib/ogc/gml/transformation.rb
+++ b/lib/ogc/gml/transformation.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_general_parameter_value_property"
 require_relative "code"
diff --git a/lib/ogc/gml/transformation_property.rb b/lib/ogc/gml/transformation_property.rb
index 59c96b6..3b80a0f 100644
--- a/lib/ogc/gml/transformation_property.rb
+++ b/lib/ogc/gml/transformation_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "transformation"
 
 module Ogc
   module Gml
-    class TransformationProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class TransformationProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :transformation, Transformation
 
       xml do
diff --git a/lib/ogc/gml/triangle.rb b/lib/ogc/gml/triangle.rb
index 8e5a115..ac715ac 100644
--- a/lib/ogc/gml/triangle.rb
+++ b/lib/ogc/gml/triangle.rb
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "shell_property"
 
 module Ogc
   module Gml
-    class Triangle < Shale::Mapper
-      attribute :interpolation, Shale::Type::String
+    class Triangle < Lutaml::Model::Serializable
+      attribute :interpolation, :string
       attribute :exterior, ShellProperty
 
       xml do
diff --git a/lib/ogc/gml/unit_definition.rb b/lib/ogc/gml/unit_definition.rb
index 0abac2f..c123f1a 100644
--- a/lib/ogc/gml/unit_definition.rb
+++ b/lib/ogc/gml/unit_definition.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -12,7 +12,7 @@
 module Ogc
   module Gml
     class UnitDefinition < AbstractTopology
-      attribute :remarks, Shale::Type::String
+      attribute :remarks, :string
       attribute :quantity_type, StringOrRef
       attribute :quantity_type_reference, Reference
       attribute :catalog_symbol, Code
diff --git a/lib/ogc/gml/unit_of_measure.rb b/lib/ogc/gml/unit_of_measure.rb
index 2966305..bc88db1 100644
--- a/lib/ogc/gml/unit_of_measure.rb
+++ b/lib/ogc/gml/unit_of_measure.rb
@@ -1,11 +1,11 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 module Ogc
   module Gml
-    class UnitOfMeasure < Shale::Mapper
-      attribute :uom, Shale::Type::Value
+    class UnitOfMeasure < Lutaml::Model::Serializable
+      attribute :uom, :string
 
       xml do
         root "unitOfMeasure"
diff --git a/lib/ogc/gml/user_defined_cs.rb b/lib/ogc/gml/user_defined_cs.rb
index b85e618..37922a6 100644
--- a/lib/ogc/gml/user_defined_cs.rb
+++ b/lib/ogc/gml/user_defined_cs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_system"
 
 module Ogc
diff --git a/lib/ogc/gml/user_defined_cs_property.rb b/lib/ogc/gml/user_defined_cs_property.rb
index 1f858a4..f19cdd1 100644
--- a/lib/ogc/gml/user_defined_cs_property.rb
+++ b/lib/ogc/gml/user_defined_cs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "user_defined_cs"
 
 module Ogc
   module Gml
-    class UserDefinedCSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class UserDefinedCSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :user_defined_cs, UserDefinedCS
 
       xml do
diff --git a/lib/ogc/gml/value_array.rb b/lib/ogc/gml/value_array.rb
index 5ab8292..141b8ad 100644
--- a/lib/ogc/gml/value_array.rb
+++ b/lib/ogc/gml/value_array.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "code"
 require_relative "code_with_authority"
@@ -11,13 +11,13 @@
 
 module Ogc
   module Gml
-    class ValueArray < Shale::Mapper
-      attribute :id, Shale::Type::Value
-      attribute :aggregation_type, Shale::Type::String
-      attribute :code_space, Shale::Type::Value
-      attribute :uom, Shale::Type::Value
+    class ValueArray < Lutaml::Model::Serializable
+      attribute :id, :string
+      attribute :aggregation_type, :string
+      attribute :code_space, :string
+      attribute :uom, :string
       attribute :meta_data_property, MetaDataProperty, collection: true
-      attribute :description, Shale::Type::String
+      attribute :description, :string
       attribute :description_reference, Reference
       attribute :identifier, CodeWithAuthority
       attribute :name, Code, collection: true
diff --git a/lib/ogc/gml/value_array_property.rb b/lib/ogc/gml/value_array_property.rb
index c65d4ec..066f1ef 100644
--- a/lib/ogc/gml/value_array_property.rb
+++ b/lib/ogc/gml/value_array_property.rb
@@ -1,18 +1,18 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_geometry"
 require_relative "abstract_time_object"
 
 module Ogc
   module Gml
-    class ValueArrayProperty < Shale::Mapper
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :abstract_value, Shale::Type::Value, collection: true
+    class ValueArrayProperty < Lutaml::Model::Serializable
+      attribute :owns, :boolean, default: -> { false }
+      attribute :abstract_value, :string, collection: true
       attribute :abstract_geometry, AbstractGeometry, collection: true
       attribute :abstract_time_object, AbstractTimeObject, collection: true
-      attribute :null, Shale::Type::Value, collection: true
+      attribute :null, :string, collection: true
 
       xml do
         root "valueComponents"
diff --git a/lib/ogc/gml/value_property.rb b/lib/ogc/gml/value_property.rb
index e064d16..5dd625a 100644
--- a/lib/ogc/gml/value_property.rb
+++ b/lib/ogc/gml/value_property.rb
@@ -1,20 +1,20 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "abstract_geometry"
 require_relative "abstract_time_object"
 
 module Ogc
   module Gml
-    class ValueProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
-      attribute :owns, Shale::Type::Boolean, default: -> { "false" }
-      attribute :abstract_value, Shale::Type::Value
+    class ValueProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
+      attribute :owns, :boolean, default: -> { false }
+      attribute :abstract_value, :string
       attribute :abstract_geometry, AbstractGeometry
       attribute :abstract_time_object, AbstractTimeObject
-      attribute :null, Shale::Type::Value
+      attribute :null, :string
 
       xml do
         root "valueComponent"
diff --git a/lib/ogc/gml/vector.rb b/lib/ogc/gml/vector.rb
index 0756e08..ebc19bf 100644
--- a/lib/ogc/gml/vector.rb
+++ b/lib/ogc/gml/vector.rb
@@ -1,12 +1,12 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "direct_position"
 
 module Ogc
   module Gml
-    class Vector < Shale::Mapper
+    class Vector < Lutaml::Model::Serializable
       attribute :content, DirectPosition
 
       xml do
diff --git a/lib/ogc/gml/vertical_crs.rb b/lib/ogc/gml/vertical_crs.rb
index 55f39f4..4a498a5 100644
--- a/lib/ogc/gml/vertical_crs.rb
+++ b/lib/ogc/gml/vertical_crs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "vertical_cs_property"
 require_relative "vertical_datum_property"
 require_relative "abstract_crs"
diff --git a/lib/ogc/gml/vertical_crs_property.rb b/lib/ogc/gml/vertical_crs_property.rb
index 5c7c56a..575a958 100644
--- a/lib/ogc/gml/vertical_crs_property.rb
+++ b/lib/ogc/gml/vertical_crs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "vertical_crs"
 
 module Ogc
   module Gml
-    class VerticalCRSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class VerticalCRSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :vertical_crs, VerticalCRS
 
       xml do
diff --git a/lib/ogc/gml/vertical_cs.rb b/lib/ogc/gml/vertical_cs.rb
index 90c457e..b812dbd 100644
--- a/lib/ogc/gml/vertical_cs.rb
+++ b/lib/ogc/gml/vertical_cs.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_coordinate_system"
 
 module Ogc
diff --git a/lib/ogc/gml/vertical_cs_property.rb b/lib/ogc/gml/vertical_cs_property.rb
index a769287..d41cd41 100644
--- a/lib/ogc/gml/vertical_cs_property.rb
+++ b/lib/ogc/gml/vertical_cs_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "vertical_cs"
 
 module Ogc
   module Gml
-    class VerticalCSProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class VerticalCSProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :vertical_cs, VerticalCS
 
       xml do
diff --git a/lib/ogc/gml/vertical_datum.rb b/lib/ogc/gml/vertical_datum.rb
index 3c001a8..4c50c7f 100644
--- a/lib/ogc/gml/vertical_datum.rb
+++ b/lib/ogc/gml/vertical_datum.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 require_relative "abstract_datum"
 
 module Ogc
diff --git a/lib/ogc/gml/vertical_datum_property.rb b/lib/ogc/gml/vertical_datum_property.rb
index 286b1d5..5688dfe 100644
--- a/lib/ogc/gml/vertical_datum_property.rb
+++ b/lib/ogc/gml/vertical_datum_property.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
-require "shale"
+require "lutaml/model"
 
 require_relative "vertical_datum"
 
 module Ogc
   module Gml
-    class VerticalDatumProperty < Shale::Mapper
-      attribute :nil_reason, Shale::Type::Value
-      attribute :remote_schema, Shale::Type::Value
+    class VerticalDatumProperty < Lutaml::Model::Serializable
+      attribute :nil_reason, :string
+      attribute :remote_schema, :string
       attribute :vertical_datum, VerticalDatum
 
       xml do
diff --git a/ogc-gml.gemspec b/ogc-gml.gemspec
index 3c81216..727422b 100644
--- a/ogc-gml.gemspec
+++ b/ogc-gml.gemspec
@@ -4,14 +4,14 @@ require_relative "lib/ogc/gml/version"
 
 Gem::Specification.new do |spec|
   spec.name = "ogc-gml"
-  spec.version       = Ogc::Gml::VERSION
-  spec.authors       = ["Ribose Inc."]
-  spec.email         = ["open.source@ribose.com'"]
+  spec.version = Ogc::Gml::VERSION
+  spec.authors = ["Ribose Inc."]
+  spec.email = ["open.source@ribose.com'"]
 
-  spec.summary       = "OGC GML data model parser"
-  spec.description   = "OGC GML data model parser"
-  spec.homepage      = "https://github.com/lutaml/ogc-gml"
-  spec.license       = "MIT"
+  spec.summary = "OGC GML data model parser"
+  spec.description = "OGC GML data model parser"
+  spec.homepage = "https://github.com/lutaml/ogc-gml"
+  spec.license = "MIT"
 
   spec.metadata["homepage_uri"] = spec.homepage
   spec.metadata["source_code_uri"] = spec.homepage
@@ -25,14 +25,14 @@ Gem::Specification.new do |spec|
       .split("\x0")
       .reject { |f| f.match(%r{^(test|spec|features)/}) }
   end
-  spec.bindir        = "exe"
-  spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
+  spec.bindir = "exe"
+  spec.executables = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
   spec.required_ruby_version = ">= 2.7.0"
 
   spec.add_runtime_dependency "nokogiri"
-  spec.add_runtime_dependency "shale"
+  spec.add_runtime_dependency "lutaml-model"
 
   spec.add_development_dependency "equivalent-xml"
   spec.add_development_dependency "pry", "~> 0.12.2"
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index cfd180b..4aff548 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -15,3 +15,10 @@
     c.syntax = :expect
   end
 end
+
+require "lutaml/model"
+require "lutaml/model/xml_adapter/nokogiri_adapter"
+
+Lutaml::Model::Config.configure do |config|
+  config.xml_adapter = Lutaml::Model::XmlAdapter::NokogiriAdapter
+end