How to make labels appear at a different scale than features' scale in Geoserver?

Question

I'm using Geoserver 2.6.2.

I need to display land parcels and their references (a number). I have specified a maxscaledenominator for the features (polygons) but I don't want references to appear at such a scale for it will be a nonsense (parcels appear very small and dense so that no additional information is needing on the map). Is it possible to specify a maxscaledenominator for labels as well?

Here is an extract of my code:

<UserStyle>
    <FeatureTypeStyle>
        <Rule>
            <MaxScaleDenominator>20000</MaxScaleDenominator>
            <PolygonSymbolizer>
                <Stroke>
                    <CssParameter name="stroke">#000000</CssParameter>
                    <CssParameter name="stroke-width">1</CssParameter>
                </Stroke>
            </PolygonSymbolizer>
            <TextSymbolizer>
                <Geometry>
                    <ogc:Function name="centroid">
                        <ogc:PropertyName>the_geom</ogc:PropertyName>
                    </ogc:Function>
                </Geometry>
                <Label>
                    <ogc:PropertyName>reference</ogc:PropertyName>
                </Label>
                <Fill>
                    <CssParameter name="fill">#000000</CssParameter>
                </Fill>
            </TextSymbolizer>
        </Rule>
    </FeatureTypeStyle>
</UserStyle>

Answer 1

Only a Rule can have a scale denominator, but that's fine as you can have as many Rules as you need. So just split your labels into another rule with its own MaxScaleDenominator, like this:

<UserStyle>
    <FeatureTypeStyle>
        <Rule>
            <MaxScaleDenominator>20000</MaxScaleDenominator>
            <PolygonSymbolizer>
                <Stroke>
                    <CssParameter name="stroke">#000000</CssParameter>
                    <CssParameter name="stroke-width">1</CssParameter>
                </Stroke>
            </PolygonSymbolizer>
         </Rule>
         <Rule>
            <MaxScaleDenominator>5000</MaxScaleDenominator>
            <TextSymbolizer>
                <Geometry>
                    <ogc:Function name="centroid">
                        <ogc:PropertyName>the_geom</ogc:PropertyName>
                    </ogc:Function>
                </Geometry>
                <Label>
                    <ogc:PropertyName>reference</ogc:PropertyName>
                </Label>
                <Fill>
                    <CssParameter name="fill">#000000</CssParameter>
                </Fill>
            </TextSymbolizer>
        </Rule>
    </FeatureTypeStyle>
</UserStyle>

Answer 2

Maybe it's too late, but you can see this https://docs.geoserver.org/latest/en/user/styling/sld/reference/textsymbolizer.html#scalable-font-size When you are in a determinate scale you put font 0 is you dont want to see

       <CssParameter name="font-size">
           <ogc:Function name="Categorize">
             <!-- Value to transform -->
             <ogc:Function name="env">
               <ogc:Literal>wms_scale_denominator</ogc:Literal>
             </ogc:Function>
             <ogc:Literal>12</ogc:Literal>
             <ogc:Literal>999999</ogc:Literal>
             <ogc:Literal>0</ogc:Literal>
             <ogc:Literal>1000000</ogc:Literal>
             <ogc:Literal>0</ogc:Literal>
           </ogc:Function>
         </CssParameter>