Adding wave pattern for natural=sand

landcover.mss

@@ -617,6 +617,10 @@
 }
 
 #landcover-area-symbols {
+  [natural = 'sand'][zoom >= 8] {
+    polygon-pattern-file: url('symbols/waves.svg');
+    polygon-pattern-alignment: global;
+  }
   [int_wetland != null][zoom >= 10] {
     polygon-pattern-file: url('symbols/wetland.svg');
     polygon-pattern-alignment: global;

project.mml

@@ -260,13 +260,13 @@ Layer:
                 END
               END AS int_wetland
           FROM planet_osm_polygon
-          WHERE ("natural" IN ('marsh', 'mud', 'wetland', 'wood', 'beach', 'shoal', 'reef', 'scrub') OR landuse = 'forest')
+          WHERE ("natural" IN ('marsh', 'mud', 'wetland', 'wood', 'beach', 'shoal', 'reef', 'scrub', 'sand') OR landuse = 'forest')
             AND building IS NULL
             AND way_area > 0.01*!pixel_width!::real*!pixel_height!::real
           ORDER BY COALESCE(layer,0), way_area DESC
         ) AS landcover_area_symbols
     properties:
-      minzoom: 10
+      minzoom: 8
   - id: icesheet-outlines
     geometry: linestring
     <<: *extents

symbols/generating_patterns/sand.md

@@ -0,0 +1,13 @@
+The sand pattern is generated by visiting http://www.imagico.de/map/jsdotpattern.php and using the following options:
+
+- random pattern ('generate' button)
+- distance = 60
+- radius = 32
+- radius y = 32
+- metric = 2
+- wave image
+- use the "render (inlined & aligned)" option 
+
+Generated SVG image is sanitized for use with Mapnik by the script svg_pattern.sh from the jsdotpattern repository at http://github.com/imagico/jsdotpattern.
+
+The final file is waves.svg