diff --git a/src/directives/gmMarkers.js b/src/directives/gmMarkers.js
index 6483128..fcf8a0c 100644
--- a/src/directives/gmMarkers.js
+++ b/src/directives/gmMarkers.js
@@ -9,7 +9,10 @@
  * To use, you specify an array of custom objects and tell the directive how to
  * extract an id and position from them. A marker will be created for each of
  * your objects. If you assign a new array to your scope variable or change the
- * array's length, the markers will also update.
+ * array's length (i.e. add or remove an object), the markers will also update.
+ * The one case where `gmMarkers` can not automatically detect changes to your
+ * objects is when you mutate objects in the array. To inform the directive of
+ * such changes, see the `gmMarkersUpdate` event below.
  *
  * Only the `gm-objects`, `gm-id` and `gm-position` attributes are required.
  *
@@ -17,7 +20,6 @@
  * These can be any objects you wish to attach to markers, the only requirement
  * is that they have a uniform method of accessing an id and a position.
  *
- *
  * @param {expression} gm-id an angular expression that given an object from
  * `gm-objects`, evaluates to a unique identifier for that object. Your object
  * can be accessed through the variable `object`. See `gm-position` below for
@@ -86,18 +88,40 @@
  * 'position_changed', write it as 'gm-on-position-changed'.
  */
 
+/**
+ * @ngdoc event
+ * @name angulargm.directive:gmMarkers#gmMarkersUpdate
+ * @eventOf angulargm.directive:gmMarkers
+ * @eventType listen on current gmMarkers scope
+ *
+ * @description Manually tell the `gmMarkers` directive to update the markers.
+ * This is useful to tell the directive when an object from `gm-objects` is
+ * mutated--`gmMarkers` can not pick up on such changes automatically.
+ *
+ * @param {string} objects Not required. The name of the scope variable which
+ * holds the objects to update markers for, i.e. what you set `gm-objects` to.
+ * It is useful because there may be multiple instances of the `gmMarkers`
+ * directive. If not specified, all instances of `gmMarkers` which are child
+ * scopes will update their markers.
+ *
+ * @example
+ * ```js
+ * $scope.$broadcast('gmMarkersUpdate', 'myObjects');
+ * ```
+ */
+ 
 /**
  * @ngdoc event
  * @name angulargm.directive:gmMarkers#gmMarkersRedraw
  * @eventOf angulargm.directive:gmMarkers
  * @eventType listen on current gmMarkers scope
  *
- * @description Force the gmMarkers directive to clear and redraw all markers.
+ * @description Force the `gmMarkers` directive to clear and redraw all markers.
  *
  * @param {string} objects Not required. The name of the scope variable which
  * holds the objects to redraw markers for, i.e. what you set `gm-objects` to.
  * It is useful because there may be multiple instances of the `gmMarkers`
- * directive. If not specified, all instances of gmMarkers which are child
+ * directive. If not specified, all instances of `gmMarkers` which are child
  * scopes will redraw their markers.
  *
  * @example
@@ -115,7 +139,7 @@
  * @description Emitted when markers are updated.
  *
  * @param {string} objects the name of the scope variable which holds the
- * objects the gmMarkers directive was constructed with. This is what
+ * objects the `gmMarkers` directive was constructed with. This is what
  * `gm-objects` was set to.
  *
  * @example
diff --git a/src/directives/gmPolylines.js b/src/directives/gmPolylines.js
index bd9f1c4..c7745ae 100644
--- a/src/directives/gmPolylines.js
+++ b/src/directives/gmPolylines.js
@@ -9,7 +9,10 @@
  * To use, you specify an array of custom objects and tell the directive how to
  * extract location data from them. A polyline will be created for each of your
  * objects. If you assign a new array to your scope variable or change the
- * array's length, the polylines will also update.
+ * array's length, the polylines will also update.  The one case where
+ * `gmPolylines` can not automatically detect changes to your objects is when
+ * you mutate objects in the array. To inform the directive of such changes,
+ * see the `gmPolylinesUpdate` event below.
  *
  * Only the `gm-objects`, `gm-id` and `gm-path` attributes are required.
  *
@@ -17,7 +20,6 @@
  * These can be any objects you wish to attach to polylines, the only requirement
  * is that they have a uniform method of accessing an id and a path.
  *
- *
  * @param {expression} gm-path an angular expression that given an object
  * from `gm-objects`, evaluates to an array of objects with lat and lng
  * properties. Your object can be accessed through the variable `object`.  For
@@ -78,6 +80,28 @@
  * 'position_changed', write it as 'gm-on-position-changed'.
  */
 
+/**
+ * @ngdoc event
+ * @name angulargm.directive:gmPolylines#gmPolylinesUpdate
+ * @eventOf angulargm.directive:gmPolylines
+ * @eventType listen on current gmPolylines scope
+ *
+ * @description Manually tell the `gmPolylines` directive to update the polylines.
+ * This is useful to tell the directive when an object from `gm-objects` is
+ * mutated--`gmPolylines` can not pick up on such changes automatically.
+ *
+ * @param {string} objects Not required. The name of the scope variable which
+ * holds the objects to update polylines for, i.e. what you set `gm-objects` to.
+ * It is useful because there may be multiple instances of the `gmPolylines`
+ * directive. If not specified, all instances of `gmPolylines` which are child
+ * scopes will update their polylines.
+ *
+ * @example
+ * ```js
+ * $scope.$broadcast('gmPolylinesUpdate', 'myObjects');
+ * ```
+ */
+ 
 /**
  * @ngdoc event
  * @name angulargm.directive:gmPolylines#gmPolylinesRedraw
diff --git a/src/services/angulargmShape.js b/src/services/angulargmShape.js
index ed4d8ca..1d5c73b 100644
--- a/src/services/angulargmShape.js
+++ b/src/services/angulargmShape.js
@@ -45,14 +45,16 @@
      */
     function _addNewElements(type, scope, controller, handlers, objectCache, optionsFn) {
       angular.forEach(objectCache, function(object, id) {
-        var elementExists = controller.hasElement(type, scope.$id, id);
+        var element = controller.getElement(type, scope.$id, id);
 
-        if (!elementExists) {
-          var options = optionsFn(object);
-          if (options == null) {
-            return;
-          }
+        var options = optionsFn(object);
+        if (options == null) {
+          return;
+        }
 
+        if (element) {
+          controller.updateElement(type, scope.$id, id, options);
+        } else {
           controller.addElement(type, scope.$id, id, options);
           var element = controller.getElement(type, scope.$id, id);
 
@@ -141,6 +143,12 @@
           updateElements(scope, scope.gmObjects());
         }
       });
+
+      scope.$on(_formatEventName('gmShapesUpdate', type), function(event, objectsName) {
+        if (objectsName == null || objectsName === attrs.gmObjects) {
+          updateElements(scope, scope.gmObjects());
+        }
+      });
     }
 
     /**
diff --git a/test/unit/directives/gmMarkersSpec.js b/test/unit/directives/gmMarkersSpec.js
index 413907f..d74ca70 100644
--- a/test/unit/directives/gmMarkersSpec.js
+++ b/test/unit/directives/gmMarkersSpec.js
@@ -43,6 +43,7 @@ describe('gmMarkers', function() {
 
     mapCtrl = elm.controller('gmMap');
     spyOn(mapCtrl, 'addElement').andCallThrough();
+    spyOn(mapCtrl, 'updateElement').andCallThrough();
     spyOn(mapCtrl, 'removeElement').andCallThrough();
     spyOn(mapCtrl, 'trigger').andCallThrough();
     spyOn(mapCtrl, 'addListener').andCallThrough();
@@ -142,7 +143,7 @@ describe('gmMarkers', function() {
     it('updates markers with removed objects', function() {
       var person = scope.people.pop();
       scope.$digest();
-      var position = new google.maps.LatLng(person.lat, person.lng);
+      var position = objToLatLng(person);
       expect(mapCtrl.removeElement).toHaveBeenCalledWith('marker', markersScopeId, '3');
     });
 
@@ -155,6 +156,17 @@ describe('gmMarkers', function() {
     });
 
 
+    it('updates markers with changed objects when update triggered', function() {
+      var person = scope.people[0]
+      person.lat = person.lat + 5;
+      person.lng = person.lng + 5;
+      var newPosition = objToLatLng(person);
+      scope.$broadcast('gmMarkersUpdate', 'people');
+      expect(mapCtrl.updateElement).toHaveBeenCalledWith('marker', markersScopeId, 
+        jasmine.any(String), {key: 'value', title: jasmine.any(String), position: newPosition});
+    });
+
+
     it('does not add null objects', function() {
       var origLength = scope.people.length;
       scope.people.push(null);
@@ -175,7 +187,7 @@ describe('gmMarkers', function() {
 
   it('triggers events', function() {
     var person = scope.people[0];
-    var position = new google.maps.LatLng(person.lat, person.lng);
+    var position = objToLatLng(person);
     var id = person.name
     scope.markerEvents = [{
       event: 'click',
@@ -192,8 +204,9 @@ describe('gmMarkers', function() {
 
 
   it('triggers events on multiple markers', function() {
-    var position0 = new google.maps.LatLng(scope.people[0].lat, scope.people[0].lng);
-    var position1 = new google.maps.LatLng(scope.people[1].lat, scope.people[1].lng);
+    
+    var position0 = objToLatLng(scope.people[0]);
+    var position1 = objToLatLng(scope.people[1]);
     var id0 = scope.people[0].name
     var id1 = scope.people[1].name
     scope.markerEvents = [{
@@ -210,7 +223,7 @@ describe('gmMarkers', function() {
 
 
   it('triggers multiple events on markers', function() {
-    var position = new google.maps.LatLng(scope.people[0].lat, scope.people[0].lng);
+    var position = objToLatLng(scope.people[0]);
     var id = scope.people[0].name
     scope.markerEvents = [
       {
@@ -308,6 +321,25 @@ describe('gmMarkers', function() {
       {key: 'differentValue', title: jasmine.any(String), id: jasmine.any(String), position: jasmine.any(Object)});
   });
 
+
+  it('listens for marker update event', function() {
+    var position1 = objToLatLng(scope.people[0]);
+    var position2 = objToLatLng(scope.people[1]);
+    scope.getOpts = function(person) {
+      return {
+        key: 'differentValue',
+        title: person.name
+      };
+    };
+    scope.$broadcast('gmMarkersUpdate', 'people');
+
+    expect(mapCtrl.updateElement).toHaveBeenCalledWith('marker', markersScopeId, 
+      jasmine.any(String), {key: 'differentValue', title: jasmine.any(String), position: position1});
+    expect(mapCtrl.updateElement).toHaveBeenCalledWith('marker', markersScopeId, 
+      jasmine.any(String), {key: 'differentValue', title: jasmine.any(String), position: position2});
+  });
+
+
   it('emits marker update event when markers updated', function() {
     var count = 0;
     scope.$on('gmMarkersUpdated', function(event, objects) {