[Mapserver-users] RE: Using Mapserver & GDAL to find elevation

[Charlton Purvis]

> Thanks Frank.  Is there any other ideas outside of mapserver, maybe?

Hi, John:

Some folks will roll their eyes when they hear this, but if you have
some sort of RGB to real_data_value lookup, then consider using
something like ImageMagick w/ your MapScript to pull the value from your
raster image.

We use it w/ our satellite imagery, and it works very well.  Basically,
once the user zooms or pans to their extent of interest and click on a
point to query, I have MapServer dump only the raster image to disk w/
the current extents.  Take that (x,y), pass it through ImageMagick to
extract the RGB from this dumped image, and then do a lookup for that
RGB in a table in our db to pull back the sea surface temperature.  Make
sure you're using a lossless image format, though, e.g. PNG.

Works like a charm.  But it ain't OGC-compliant!

If you want more info or code, let me know.

Charlton