[mapserver-users] Identify for raster data?

[Frank Warmerdam]

Steve Lime wrote:

> We'd simply need a msGetClosestPixel() function for each supported
> raster type. Perhaps a msGetPixelWindow() would make more sense
> then a few metrics could be calculated. With that function I could
> easily roll a result set. Of course we need time to write those functions.
> (ideas Frank?).


Steve,

It would be relatively easy to implement this for GDAL but a fair amount of
work if you want to have it for all supported formats.  I would add, that
all the rules for opening files and identifying formats is currently done
in msDrawRasterLayer().  If we want to take other actions on raster files,
we might want to be able to preserve an open handle to the file through a
longer time.

If we did want to implement msGetPixelWindow() what would it be passed?
A georeferenced location?  What should we return for pixels off the database?
Do we support arbitrary window sizes?  What statistics do you want a local
window instead of just one pixel for?

Best regards,

-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent