mapnik/tests/data/good_maps/glyph_symbolizer.xml

<Map minimum-version="0.7.2">
    <Style name="arrows">
    <Rule>
      <GlyphSymbolizer size="10" char="'&#237;'" value="[value]" angle="[azimuth]+90" face-name="DejaVu Sans Condensed" allow-overlap="1" avoid-edges="0" halo-fill="rgba(0%,0%,0%,.1)" halo-radius="1" angle-mode="azimuth">
        <RasterColorizer default_mode="discrete" default_color="#000000">
          <stop value="0" color="#0044cc"/>
          <stop value="10" color="#00cc00"/>
          <stop value="20" color="#ffff00"/>
        </RasterColorizer>
      </GlyphSymbolizer>
    </Rule>
  </Style>
</Map>