Old Geoserver install ("2.1.?") will not validate Transformation element in Heatmap SLD XML

Question

I'm stuck with an old, weird version of Geoserver in our production environment (circa 2011, installed in an opengeo-suite directory). It seems the WPS extension is installed. On my http://www.our-domain.com/geoserver/web/ page, we've got the following details:

"..is running version 2.1-SNAPSHOT."

As well as Service Capabilities WPS 1.0.0 ..which leads me to believe the WPS extension is installed.

To establish the Geoserver style/layer config, I've followed the heatmap example in the Geoserver docs, as well as this one published by Boundless, in addition to a few others. They're all mostly identical with respect to the SLD, except for the first child element of the Transformation element tends to have one of two different name values..

<ogc:Function name="gs:Heatmap"> or <ogc:Function name="vec:Heatmap">

It doesn't matter which parameter value I use, Geoserver's SLD validator throws the following error concerning my SLD definition (bold emphasis mine):

org.xml.sax.SAXParseException; lineNumber: 14; columnNumber: 25; cvc-complex-type.2.4.a: Invalid content was found starting with element 'Transformation'. One of '{"http://www.opengis.net/sld":Name, "http://www.opengis.net/sld":Title, "http://www.opengis.net/sld":Abstract, "http://www.opengis.net/sld":FeatureTypeName, "http://www.opengis.net/sld":SemanticTypeIdentifier, "http://www.opengis.net/sld":Rule}' is expected.

I can add additional nodes, particuarly for FeatureTypeName and SemanticTypeIdentifier, and I can reduce this error to just, basically, "{Rule}' is expected". However I'm guessing about adding these extra nodes, and none of the examples I'm finding include them.. which further reduces my confidence that I'm on the right track.

It may be that our Geoserver version is simply too old for these renderers, but I thought I saw a 1.8 doc that had a similar example so I have to assume something else is amiss. FWIW this is my SLD xml, but it's basically the same as the Boundless example. Does anyone have any helpful insights?

<?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>Heatmap</Abstract>
      <FeatureTypeStyle>
        <Transformation>
         <ogc:Function name="gs:Heatmap">
           <ogc:Function name="parameter">
             <ogc:Literal>data</ogc:Literal>
           </ogc:Function>
           <ogc:Function name="parameter">
             <ogc:Literal>radiusPixels</ogc:Literal>
             <ogc:Function name="env">
               <ogc:Literal>radius</ogc:Literal>
               <ogc:Literal>100</ogc:Literal>
             </ogc:Function>
           </ogc:Function>
           <ogc:Function name="parameter">
             <ogc:Literal>pixelsPerCell</ogc:Literal>
             <ogc:Literal>10</ogc:Literal>
           </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>
          <RasterSymbolizer>
            <Geometry>
              <ogc:PropertyName>the_geom</ogc:PropertyName>
            </Geometry>
            <Opacity>0.6</Opacity>
            <ColorMap type="ramp" >
              <ColorMapEntry color="#FFFFFF" quantity="0"    label="nodata" opacity="0" />
              <ColorMapEntry color="#FFFFFF" quantity="0.02" label="nodata" opacity="0" />
              <ColorMapEntry color="#4444FF" quantity=".1"   label="nodata" />
              <ColorMapEntry color="#FF0000" quantity=".5"   label="values" />
              <ColorMapEntry color="#FFFF00" quantity="1.0"  label="values" />
            </ColorMap>
          </RasterSymbolizer>
        </Rule>
      </FeatureTypeStyle>
    </UserStyle>
  </NamedLayer>
</StyledLayerDescriptor>

Answer 1

There is a very real chance that the raster transforms are not supported by a GeoServer that old. Why not just upgrade? it's free!

Anyway, things to check:

1. does it work? You can ignore the validator, as often the schema it is using lags behind what the actual code will accept.

2. Look in the WPS getCapabilities response to find out what the process is called, over time the prefixes have changed but either of those should work if the process exists.

3. Upgrade to a recent GeoServer (2.13.x) and all your issues will be gone.