Using WKT in SLD

Question

I have a Point geometry and need to draw some shape (a Polygon for now) when styling.

Lets say I have this SLD:

<Rule>
  <PointSymbolizer>
    <Graphic>
      <Mark>
        <WellKnownName>wkt://POLYGON((0 0,1 0,1 1,0 1,0 0))</WellKnownName>
        <Fill>
          <CssParameter name="fill">#009900</CssParameter>
          <CssParameter name="fill-opacity">0.4</CssParameter>
        </Fill>
      </Mark>
      <Rotation>0</Rotation>
    </Graphic>
  </PointSymbolizer>
</Rule>

Having my map in EPSG:4326, what do "1" and "0" in the Polygon definition rules mean?

I can see little squares in my map indeed, but don't know why.

Answer 1

In general SLD uses pixels for it's measurements, you can switch to ground units by adding a parameter uom to the Symbolizer:

<PointSymbolizer uom="http://www.opengeospatial.org/se/units/metre">