DEM to topographic contour lines

[Zenon Panoussis]

Bruno Patini Furtado wrote:

> I need MapServer to display the topography of a terrain based on a DEM
> file (http://en.wikipedia.org/wiki/DEM). Is there any configuration
> out-of-the-box for example in the LAYER element of the Map file? 

 LAYER
    NAME "ETOPO2"
    TYPE RASTER
    STATUS DEFAULT
    DATA "/vol/gis/etopo2/etopo2.tif"
    PROCESSING "DITHER=YES"
    PROCESSING "SCALE=AUTO"
    MINSCALE 5000000
    CLASS
      NAME "Elevation above 8000m"
      EXPRESSION ([pixel]>=8000)
      COLOR 98 0 0
    END
    CLASS
      NAME "Elevation 7500-8000m"
      EXPRESSION ([pixel]>=7500 AND [pixel]<8000)
      COLOR 106 8 0
    END
# and so on ad absurdum...
  END

> It would be necessary to define specific ranges and for each one a
> particular color.

Yes, and you will then meet the woes of harmonic colour scales; it's
a bitch. http://www.colorbrewer.org/ might be of some help, but it
only produces relatively short ranges. There must be some tool around
that produces colour scales programmatically, but I haven't found it.

You might also want to avoid the format hell I went through a couple
of weeks ago by checking http://www.nabble.com/Raster-tiling-t1985377.html .

Z