I am working with Geoserver for some weeks now and were able to deploy some services already. For my thematic map (e.g. temperature) I created a custom style displaying all tiles in specific colors (blue, yellow, red). Therefore I want to create a legend, but I really dont know how to do this. This legend should show 3 polygons in 3 different colors and some text right of it. Something like "[red polygon] > 30".

custom style sld:

    <?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>Temperature</Name>
        <UserStyle>
          <Title>My Temperature Style</Title>
          <FeatureTypeStyle>
            <Rule>
    			<PolygonSymbolizer>
    			   <Fill>
    				 <CssParameter name="fill">
    				   <ogc:Function name="Interpolate">
    					 <ogc:PropertyName>dTA</ogc:PropertyName>
    
    					 <ogc:Literal>0</ogc:Literal>
    					 <ogc:Literal>#0000ff</ogc:Literal>
    
    					 <ogc:Literal>15</ogc:Literal>
    					 <ogc:Literal>#ffff00</ogc:Literal>
    
    					 <ogc:Literal>30</ogc:Literal>
    					 <ogc:Literal>#ff0000</ogc:Literal>
    					 
    					 <ogc:Literal>color</ogc:Literal>
    				   </ogc:Function>
    				 </CssParameter>
    			   </Fill>
    			</PolygonSymbolizer>
            </Rule>
          </FeatureTypeStyle>
        </UserStyle>
       </NamedLayer>
    </StyledLayerDescriptor>