Using COLORRANGE to display DEM data

[Jeff Hoffmann]

Frank Warmerdam wrote:
> Jeff Hoffmann wrote:
>> I'm trying to use the COLORRANGE feature to display DEM data, but I'm 
>> not getting any output from what I'm doing now.  I have a tif with one 
>> band (the elevation) and I'm trying to first split that band into 
>> different classes for elevation ranges then I want to use a color ramp 
>> within each class to get a smooth blue->green->yellow->red sort of 
>> transition.  The first split into classes seems to work -- I can 
>> assign each class a solid color and I'll see that, I just can't get 
>> the color ramp to work within the class.  Here's one of my class 
>> definitions:
>>
>>   CLASS
>>     EXPRESSION ([pixel] >= 500 AND [pixel] < 1000)
>>     STYLE
>>       COLORRANGE 48 255 180 255 255 0
>>       DATARANGE 500 1000
>>       RANGEITEM "[pixel]"
>>     END
>>   END
>>
>> Does anybody know what's going wrong here?
> 
> Jeff,
> 
> Excellent idea, but unfortunately the raster colorrange support only
> works with one class, and a single color range.  This is a limitation
> of the implementation.

Thanks for the confirmation, Frank.  I'm kind of disappointed that this 
won't work, but I've found a couple of simple little utility programs 
that will let me pre-process the TIFFs into the color-shaded output I 
wanted.  If anybody else is interested, they're located at 
http://www.perrygeo.net/wordpress/?p=7  Overlaying a hillshaded version 
at ~40% opacity on top of the color ramp make for some really nice 
looking images with almost no work involved.

--
Jeff Hoffmann
Head Plate Spinner
PropertyKey.com