dynamic colorization of raster elevation data in mapnik and mapserver styles

mapnik.xml

<!-- renders: http://cl.ly/0t3p3D0a320x0I0M2o2S -->

<Map srs="+init=epsg:4269">

    <Style name="terrain">
        <Rule>
          <RasterSymbolizer>
            <!-- http://trac.mapnik.org/wiki/RasterColorizer -->
            <RasterColorizer default-mode="linear">
              <stop color="#35A86E" value = "1003"/>
              <stop color="#FBFF80" value = "1800"/>
              <stop color="#E06C1F" value = "2800"/>
              <stop color="#C83737" value = "3500"/>
              <stop color="#D7F3F3" value = "4397"/>
            </RasterColorizer>
          </RasterSymbolizer>
        </Rule>
    </Style>

    <Datasource name="terrain">
        <Parameter name="type">gdal</Parameter>
        <Parameter name="band">1</Parameter>
        <Parameter name="base">../../data/</Parameter>
    </Datasource>

    <Layer name="hillshade" srs="+init=epsg:4269">
        <StyleName>terrain</StyleName>
        <Datasource base="terrain">
            <Parameter name="file">NED_17672037.bil</Parameter>
        </Datasource>
    </Layer>
    <Layer name="hillshade" srs="+init=epsg:4269">
        <StyleName>terrain</StyleName>
        <Datasource base="terrain">
            <Parameter name="file">NED_35378829.bil</Parameter>
        </Datasource>
    </Layer>
    <Layer name="hillshade" srs="+init=epsg:4269">
        <StyleName>terrain</StyleName>
        <Datasource base="terrain">
            <Parameter name="file">NED_68314046.bil</Parameter>
        </Datasource>
    </Layer>
    <Layer name="hillshade" srs="+init=epsg:4269">
        <StyleName>terrain</StyleName>
        <Datasource base="terrain">
            <Parameter name="file">NED_82481338.bil</Parameter>
        </Datasource>
    </Layer>
    <Layer name="hillshade" srs="+init=epsg:4269">
        <StyleName>terrain</StyleName>
        <Datasource base="terrain">
            <Parameter name="file">NED_23900111.bil</Parameter>
        </Datasource>
    </Layer>
    <Layer name="hillshade" srs="+init=epsg:4269">
        <StyleName>terrain</StyleName>
        <Datasource base="terrain">
            <Parameter name="file">NED_56441553.bil</Parameter>
        </Datasource>
    </Layer>
    <Layer name="hillshade" srs="+init=epsg:4269">
        <StyleName>terrain</StyleName>
        <Datasource base="terrain">
            <Parameter name="file">NED_81400742.bil</Parameter>
        </Datasource>
    </Layer>
    <Layer name="hillshade" srs="+init=epsg:4269">
        <StyleName>terrain</StyleName>
        <Datasource base="terrain">
            <Parameter name="file">NED_98513935.bil</Parameter>
        </Datasource>
    </Layer>

</Map>

mapserver.map

LAYER
  NAME "hillshade"
  TYPE raster
  TILEINDEX "/benchmarking/wms/2011/data/raster/DEM/bil_16int/dem_bil16int.shp"
  PROJECTION
       "+init=epsg:4326" 
  END
 # OPACITY 60
  PROCESSING "SCALE=1003,1800"
  CLASS
    STYLE
      COLORRANGE  46 154 88 251 255 128  # 242 239 233 0 0 255  #34  139  34   0 0  255
      DATARANGE   1003 1800
    END
  END
END


LAYER
  NAME "hillshade"
  TYPE raster
  TILEINDEX "/benchmarking/wms/2011/data/raster/DEM/bil_16int/dem_bil16int.shp"
  PROJECTION
       "+init=epsg:4326"
  END
 # OPACITY 60
  PROCESSING "SCALE=1800,2800"
  CLASS
    STYLE
      COLORRANGE  251 255 128 224 108 31 
      DATARANGE   1800 2800
    END
  END
END

LAYER
  NAME "hillshade"
  TYPE raster
  TILEINDEX "/benchmarking/wms/2011/data/raster/DEM/bil_16int/dem_bil16int.shp"
  PROJECTION
       "+init=epsg:4326"
  END
#  OPACITY 60
  PROCESSING "SCALE=2800,3500"
  CLASS
    STYLE
      COLORRANGE   224 108 31  200 55 55
      DATARANGE    2800 3500
    END
  END 
END


LAYER
  NAME "hillshade"
  TYPE raster
  TILEINDEX "/benchmarking/wms/2011/data/raster/DEM/bil_16int/dem_bil16int.shp"
  PROJECTION
       "+init=epsg:4326"
  END
#  OPACITY 60
  PROCESSING "SCALE=3500,4397"
  CLASS
    STYLE
      COLORRANGE  200 55 55  215 244 244 
      DATARANGE   3500 4397
    END
  END
END