building-symbolizer-shadow.xml

<Map srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs" 
  background-image="../../data/images/pattern.png"
  >
    <Parameters>
        <Parameter name="sizes">512, 512</Parameter>
        <Parameter name="bbox">-20,-20,120,120</Parameter>
    </Parameters>
    <Style name="ellipse">
        <Rule>
            <BuildingSymbolizer
                height="70"
                fill="grey"
                fill-opacity="1"
                shadow-length="90"
                shadow-opacity="0.2"
                shadow-angle="30"
                />
        </Rule>
    </Style>

    <Layer name="layer" srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
        <StyleName>ellipse</StyleName>
        <Datasource>
            <Parameter name="type">csv</Parameter>
            <Parameter name="inline">
i|wkt
1|POLYGON((90 40,50 0,10 40,50 80,90 40))
            </Parameter>
        </Datasource>
    </Layer>
</Map>