[gdal-dev] reading features without loading geometries

[Frank Warmerdam]

Milton Jonathan wrote:
> Hello Frank
> 
> Thanks a lot for your quick answer! I guess that approach will do in 
> practice, since large data will usually be in a RDBMS. Actually, I also 
> thought about this, but I didn't have a spatial database at hand (I did 
> test it on a shapefile, but as you said in that case the driver loads 
> the geometry anyway..)
> 
> Well, another similar thing that I was trying to do was to just load the 
> Envelope of each object without loading the whole geometry. Do you think 
> that would be possible with OGR? The reason for doing this is to quickly 
> scan all the objects' bounding boxes in order to build a spatial tree 
> for caching purposes. It would be great if we could do that!

Milton,

I can't think of any way of just getting envelopes without OGR internally
still having to load the whole geometry.  Internally within some drivers
they are able to take advantage of bounding box info in the format itself
to accelerate spatial filtering but this isn't exposed except through the
ability to do a SetSpatialFilter().

Best regards,
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