Drawing Raster Query Results

[Frank Warmerdam]

Folks,

A couple years ago I implemented support for "query" against a raster layer.
Such queries essentially return a list of point features, generally one for
each pixel that satisfies the query criteria.

Recently a user has run into problems when they try to draw a map of the
query result.  This isn't something I've ever tried before, and to be honest,
I'm a bit vague on how queries are normally used in MapServer.  I assumed they
were mostly used for populating tabular results which does work fine.

The drawing a query layer for a map result doesn't work properly, as documented
in:

   http://trac.osgeo.org/mapserver/ticket/2069

The question, to my mind, is whether it makes sense to try and draw point
features from a raster query result on a map, and if we did so how do we
differentiate styling used for the raster from styling used for the query
results which are a very different sort of data.

I'm tempted to modify msDrawQueryLayer() to do nothing raster layers, but to 
issue a debug message indicating that the layer is being skipped since drawing 
raster query results is considered an unclear request.

If anyone has an opinion contrary to my idea to disallow this, please let me
know on this list, or via the ticket.

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    | President OSGeo, http://osgeo.org