Render bare_rock pattern in landcover-area-symbols

landcover.mss

@@ -490,14 +490,11 @@
 
   [feature = 'natural_bare_rock'][zoom >= 5] {
     polygon-fill: @bare_ground;
-    polygon-pattern-file: url('symbols/rock_overlay.png');
     [way_pixels >= 4] {
       polygon-gamma: 0.75;
-      polygon-pattern-gamma: 0.75;
     }
     [way_pixels >= 64] {
       polygon-gamma: 0.3;
-      polygon-pattern-gamma: 0.3;
     }
   }
 
@@ -720,6 +717,15 @@
     }
   }
 
+  [natural = 'bare_rock'][zoom >= 5] {
+    polygon-pattern-file: url('symbols/bare_rock5.png');
+    [way_pixels >= 4] {
+      polygon-pattern-gamma: 0.75;
+    }
+    [way_pixels >= 64] {
+      polygon-pattern-gamma: 0.3;
+    }
+  }
   [natural = 'sand'][zoom >= 5] {
     polygon-pattern-file: url('symbols/beach.png');
     polygon-pattern-alignment: global;

project.mml

@@ -289,7 +289,7 @@ Layer:
             tags->'leaf_type' AS leaf_type,
             way_area/NULLIF(POW(!scale_denominator!*0.001*0.28,2),0) AS way_pixels
           FROM planet_osm_polygon
-          WHERE ("natural" IN ('mud', 'wetland', 'wood', 'beach', 'shoal', 'reef', 'scrub', 'sand') OR landuse = 'forest')
+          WHERE ("natural" IN ('bare_rock', 'mud', 'wetland', 'wood', 'beach', 'shoal', 'reef', 'scrub', 'sand') OR landuse = 'forest')
             AND building IS NULL
             AND way_area > 1*!pixel_width!::real*!pixel_height!::real
           ORDER BY COALESCE(layer,0), way_area DESC

symbols/generating_patterns/bare_rock.md

@@ -0,0 +1,7 @@
+Pattern file for bare_rock is generated in 2 steps.
+
+For the pattern visit [jsdotpattern (command sequence is recorded)](http://www.imagico.de/map/jsdotpattern.php#x,256,jdp18277;g,5,32,32;rx,25,2,32,32;rx,25,2,32,32;rx,25,2,32,32;rx,25,2,32,32;rx,25,2,32,32;rd,0,0,1,rock,0.1,24,24,0,jdp75459,8a99a5,eee5dc;)
+
+Generate file - use "render" followed by using "get pattern SVG data" (it is expected that background will be transparent, background colour in jsdotpattern is only for display).
+
+However, since SVG patterns is not properly handled by Mapnik at this time, the SVG file was converted to a PNG file with alpha channel, allotments.png