mapnik/tests/visual_tests/styles/polygon-winding-order.xml

<Map
    background-color="#000"
    srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
    <Parameters>
        <Parameter name="sizes">300,300</Parameter>
    </Parameters>

    <Style name="polygon">
        <Rule>
            <PolygonSymbolizer fill="#800000" />
            <LineSymbolizer stroke="#ff0000" stroke-width="2" offset="4" />
        </Rule>
    </Style>

    <Style name="frame">
        <Rule>
            <PolygonSymbolizer />
        </Rule>
    </Style>
    <!--
      frame is a layer with a single polygon that is used to ensure that
       m.zoom_all() will zoom the map to a reasonable bounding extent
    -->
    <Layer name="frame" srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
        <StyleName>frame</StyleName>
        <Datasource>
            <Parameter name="type">csv</Parameter>
            <Parameter name="inline">
wkt|name
Polygon((-75.0 -75.0, -75.0 75.0, 35.0 75.0, 35.0 -75.0, -75.0 -75.0))|bounds
            </Parameter>
        </Datasource>
    </Layer>

    <!--
      The inline GeoJSON has two polygons with different winding order
      (clockwise and counterclockwise), and each of those has two inner rings
      (again, one clockwise and one counterclockwise)
    -->

    <Layer name="bug" srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
        <StyleName>polygon</StyleName>
        <Datasource>
            <Parameter name="type">geojson</Parameter>
            <Parameter name="inline">{
"type": "FeatureCollection",
"crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },

"features": [
{ "type": "Feature", "properties": { }, "geometry": { "type": "Polygon", "coordinates":
    [ [ [ 30, -20 ], [ -70, -20 ], [ -70, -70 ], [ 30, -70 ], [ 30, -20 ] ],
      [ [ -60, -30 ], [ -30, -30 ], [ -30, -60 ], [ -60, -60 ], [ -60, -30 ] ],
      [ [ -10, -30 ], [ -10, -60 ], [ 20, -60 ], [ 20, -30 ], [ -10, -30 ] ]
      ] } },
{ "type": "Feature", "properties": { }, "geometry": { "type": "Polygon", "coordinates":
    [ [ [ -70, 70 ], [ 30, 70 ], [ 30, 20 ], [ -70, 20 ], [ -70, 70 ] ],
      [ [ -60, 60 ], [ -30, 60 ], [ -30, 30 ], [ -60, 30 ], [ -60, 60 ] ],
      [ [ 20, 30 ], [ 20, 60 ], [ -10, 60 ], [ -10, 30 ], [ 20, 30 ] ]
      ] } }
]
}</Parameter>
        </Datasource>
    </Layer>
</Map>