GeoServer - Assign color to the feature based on HEX/RGB value from the attribute

Question

I need to color polygons based on HEX value from attribute. Is that possible?

To create categories by colors is not really good solution for me, since in future more colors will be added which I don't know at this point. And I want to avoid editing style each time.

GeoServer version 2.23.2. Data sourced in PostgreSQL databse.

Tried to create such SLD style in QGIS but don't see any ways to do that.

Answer 1

There are two ways to accomplish this. If you want to colour your polygon layer based on hard-coded values, you can achieve this by obtaining the HEX colour from the layer and assigning it to your SLD variable, where "Color" is the field containing HEX values.

<PolygonSymbolizer>
    <Fill>
        <CssParameter name="fill">
            <ogc:PropertyName>Color</ogc:PropertyName>
        </CssParameter>
    </Fill>
    <Stroke>
        <CssParameter name="stroke">#000000</CssParameter>
        <CssParameter name="stroke-width">1</CssParameter>
    </Stroke>
</PolygonSymbolizer>

In another case, you can use the interpolate approach so you don't need to specify any hard-coded colour value in your data. In the following code, "Value" is the field you want to symbolize your data based on that.

<PolygonSymbolizer>
   <Fill>
     <CssParameter name="fill">
       <ogc:Function name="Interpolate">
         <!-- Property to transform -->
         <ogc:PropertyName>Value</ogc:PropertyName>

         <!-- Mapping curve definition pairs (input, output) -->
         <ogc:Literal>0</ogc:Literal>
         <ogc:Literal>#fefeee</ogc:Literal>

         <ogc:Literal>9000000</ogc:Literal>
         <ogc:Literal>#00ff00</ogc:Literal>

         <ogc:Literal>23000000</ogc:Literal>
         <ogc:Literal>#ff0000</ogc:Literal>

         <!-- Interpolation method -->
         <ogc:Literal>color</ogc:Literal>

         <!-- Interpolation mode - defaults to linear -->
       </ogc:Function>
     </CssParameter>
   </Fill>
</PolygonSymbolizer>