[Mapserver-users] Query Raster Layer for Pixel Values

[John Norton]

Sorry I missed the meeting in Ottawa. Frank W. probably discussed 
querying raster layers in his workshop. Basically, I would like to a 
query a raster layer (8 bit or 16 bit if possible) with a bounding 
rectangle or possibly a user selected/defined shape and apply a function 
to each of the pixel values, eg find the average value. Or could a query 
just return a vector with the pixel values. I don't need the spatial 
location for each, just the DN value. Any ideas how this may be done 
with MS or where might I start?
Thanks
John Norton
Remote Sensing Applications Center
US Forest Service
Salt Lake City, Utah