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I have a large field of randomly distributed points (100,000 of them to be precise), and I'd like to get values for a variety of raster and polygon coverages for each point. I've been using the QGIS Point Sampling Tool, and it seems to work very nicely for rasters (runs in under a minute) but to take literally hours for many of my polygon coverages.

Can someone explain to me why this is taking so long?

Is there a more efficient open source tool to do this?

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I wonder if you might be able to use the Add polygon attributes to points tool in the Processing toolbox? (much faster than the standard spatial join according to this blogpost: http://anitagraser.com/2013/10/02/add-polygon-attributes-to-points-vs-join-attributes-by-location/)

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    Perfect! Since it took a little digging for me to realize this, the Plugin that is needed is Sextante, and SAGA must be installed. – user1521655 Oct 3 '13 at 20:13
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For polygons, instead of the Point Sampling tool, you could try doing a spatial join, which may be quicker (depending on the implementation of the Point Sampling tool - which works well for rasters, but I don't use it on vectors myself).

  • It looks like spatial join is similarly slow. Neuhausr's comment has solved my problem, though! – user1521655 Oct 3 '13 at 20:16

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