[postgis-users] Raster Support...

Stephen Marshall smarshall at wsi.com
Fri Aug 25 13:46:01 PDT 2006


John,

Regarding your raster data wish:

>I would like to be able to intersect vector geometries with a range (or
>ranges) of raster values.  An example, given a DEM, what schools would flood
>given a 2m rise in water.  Or, given a NEXRAD raster, what facility is
>getting hit by extreme rain.

I agree with the sentiment.  However, I think it could be achieved by first 
generating a polygon geometry for the area of interest (using the "filled
contouring" capability I've wished for), then using standard PostGIS 
spatial relationship functions to relate the raster-derived polygon to
other geographic features.

I think if we focus on being able to generate geometry objects from 
rasters, we can eliminate the need to implement spatial relationship
operators that work on individual pieces of rasters (e.g. pixels).  
I think this divide-and-conquer strategy would make the bounds of raster
functionality more tractable to implement, because it leverages so much
of what is already in PostGIS.  




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