[postgis-devel] Which intersection is faster?
dustymugs at gmail.com
Sat Mar 23 10:30:08 PDT 2013
I'd suggest using the variant that runs in raster space. If I
remember correctly, some changes have been made to this in 2.1.
On Sat, Mar 23, 2013 at 10:20 AM, Jorge Arévalo
<jorgearevalo at libregis.org> wrote:
> I don't know if this is a naive question, but in ST_Intersects description (http://postgis.net/docs/manual-2.0/RT_ST_Intersects.html) I read:
> "Depending on the order that the raster and geometry is passed to ST_Intersects(), the test will operate in either raster-space or geometry-space. If ST_Intersects(raster, ....), the test is in raster-space (the geometry is converted to a raster). If ST_Intersects(geometry, ...), the test is in geometry-space (the raster is converted to a set of pixel polygons)."
> My question: in equal conditions, which version should be faster?
> ST_Intersects(raster, vector) --> in raster space
> ST_Intersects(vector, raster) --> in vector space
> Many thanks in advance,
> Jorge Arevalo
> Freelance developer
> Enviado con Sparrow (http://www.sparrowmailapp.com/?sig)
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