Adds default value for raster overviews configuration

config/environments/development.js.example

@@ -63,6 +63,7 @@ var config = {
         */
         row_limit: 65535,
         simplify_geometries: true,
+        use_overviews: true, // use overviews to retrieve raster
         /*
          * Set persist_connection to false if you want
          * database connections to be closed on renderer

config/environments/production.js.example

@@ -65,6 +65,7 @@ var config = {
          */
         persist_connection: false,
         simplify_geometries: true,
+        use_overviews: true, // use overviews to retrieve raster
         max_size: 500
     }
     ,mapnik_version: undefined

config/environments/staging.js.example

@@ -57,6 +57,7 @@ var config = {
         extent: "-20037508.3,-20037508.3,20037508.3,20037508.3",
         row_limit: 65535,
         simplify_geometries: true,
+        use_overviews: true, // use overviews to retrieve raster
         /*
          * Set persist_connection to false if you want
          * database connections to be closed on renderer

config/environments/test.js.example

@@ -57,6 +57,7 @@ var config = {
         extent: "-20037508.3,-20037508.3,20037508.3,20037508.3",
         row_limit: 65535,
         simplify_geometries: true,
+        use_overviews: true, // use overviews to retrieve raster
         /*
          * Set persist_connection to false if you want
          * database connections to be closed on renderer