[Gdal-dev] shaded relief utility

[Bryan Keith]

Ethan Alpert wrote:

>One way to accomplish this is to color a vector topo set and overlay it
>with partial transparency over a grey scale hill shade relief.
>
>  
>
Ethan,

How do you create the vector topo set from the DEM?

That's essentially the question I asked to a couple gis lists (though 
not this one) a few weeks ago, and I didn't get any answers.  The output 
must be closed polygons attributed with the data range of the DEM that 
the polygon encloses, and the polygons must look like the results of a 
contouring algorithm, not along the jagged cell edges of the input data, 
just like the dataset on the demis website.

Bryan

>I believe this is how demis does it. Check out the map server below.
>Turn off all layers except hillshading and topography. Zoom in to an
>area and toggle one of those two layers. You'll see what I'm talking
>about.
>
>http://www.demis.nl/home/pages/wms/demiswms.htm
>
>-----Original Message-----
>From: gdal-dev-bounces at lists.maptools.org
>[mailto:gdal-dev-bounces at lists.maptools.org] On Behalf Of Paul Surgeon
>Sent: Tuesday, December 13, 2005 1:04 PM
>To: Brent Fraser
>Cc: gdal-dev at lists.maptools.org
>Subject: Re: [Gdal-dev] shaded relief utility
>
>
>On Monday 12 December 2005 23:32, Brent Fraser wrote:
>  
>
>>Paul, Matt,
>>
>>  And it compiled ok on Windows.  I justed editted the makefile.vc 
>>file to include hillshade.exe.  I haven't actually tried it yet.
>>
>>  Like Paul,  I'm actually interested in shading an image file based 
>>on a DEM (if that's what you meant, Paul)
>>
>>Brent
>>    
>>
>
>No, I meant I need a way to make "color scaled relief maps" (or whatever
>they 
>are called in GIS lingo) from DEMs. The type that has a color gradient
>based 
>on the altitude.
>
>It's pretty simple so I find it hard to believe no one has written an
>open 
>source utility to do it. It's just a matter of trying to find out what's
>
>available.
>
>I take it what you're after is a way to modulate an existing base image
>with a 
>hillshade image generated from a DEM.
>
>Paul
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>  
>