[gdal-dev] Calculate footprints of shapefiles

[Christopher Barker]

> thanks for the hints. So a sort of Union operation seems to be necessary. I need to check how fast that is with OGR on larger shapefiles (I want to store in PostGIS just the footprint, not the full geometry collection). The Convex Hull could be a good alternative to a simplified boundary.

it depends on your shapes -- if you have a very concave shape, a convex 
hull can be a poor representation.

You might try simplifying before the Union - that would make the Union 
faster.

-Chris



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