SLD Style

<?xml version="1.0" encoding="ISO-8859-1"?>
   <StyledLayerDescriptor version="1.0.0"
       xsi:schemaLocation="http://www.opengis.net/sld StyledLayerDescriptor.xsd"
       xmlns="http://www.opengis.net/sld"
       xmlns:ogc="http://www.opengis.net/ogc"
       xmlns:xlink="http://www.w3.org/1999/xlink"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
     <NamedLayer>
       <Name>Heatmap</Name>
       <UserStyle>
         <Title>Heatmap</Title>
         <Abstract>A heatmap surface showing population density</Abstract>
         <FeatureTypeStyle>
           <Transformation>
             <ogc:Function name="aaa:Decimation">
               <ogc:Function name="parameter">
                 <ogc:Literal>data</ogc:Literal>
               </ogc:Function>
               <ogc:Function name="parameter">
                 <ogc:Literal>pixelSize</ogc:Literal>
                 <ogc:Function name="env">
                   <ogc:Literal>radius</ogc:Literal>
                   <ogc:Literal>8</ogc:Literal>
                 </ogc:Function>
               </ogc:Function>
               <ogc:Function name="parameter">
                 <ogc:Literal>outputBBOX</ogc:Literal>
                 <ogc:Function name="env">
                   <ogc:Literal>wms_bbox</ogc:Literal>
                 </ogc:Function>
               </ogc:Function>
               <ogc:Function name="parameter">
                 <ogc:Literal>outputWidth</ogc:Literal>
                 <ogc:Function name="env">
                   <ogc:Literal>wms_width</ogc:Literal>
                 </ogc:Function>
               </ogc:Function>
               <ogc:Function name="parameter">
                 <ogc:Literal>outputHeight</ogc:Literal>
                 <ogc:Function name="env">
                   <ogc:Literal>wms_height</ogc:Literal>
                 </ogc:Function>
               </ogc:Function>
             </ogc:Function>
           </Transformation>
    <Rule>
          <Name>rule1</Name>
          <Title>Red Square</Title>
          <Abstract>A 6 pixel square with a red fill and no stroke</Abstract>
            <PointSymbolizer>
              <Graphic>
                <Mark>
                  <WellKnownName>square</WellKnownName>
                  <Fill>
                    <CssParameter name="fill">#FF0000</CssParameter>
                  </Fill>
                </Mark>
              <Size>6</Size>
            </Graphic>
          </PointSymbolizer>
        </Rule>
         </FeatureTypeStyle>
       </UserStyle>
     </NamedLayer>
    </StyledLayerDescriptor>