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I have a vector layer of counties in Florida and a layer of points. I want to count the number of points that lie within 10km of the boundary for each county pair. This is what this looks like in QGIS -- any ideas on an efficient way to do this?

points

  • Have you tried creating a buffer on that line? – BradHards Mar 5 '14 at 20:01
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    Its actually all the counties in the state that I want this separation for. Here is the full picture: link I'm taking a look at buffers,are you suggesting that I create a layer with buffers and they using point-in-polygon? I'm very new to QGIS so any help would be great! – figuringout Mar 5 '14 at 21:13
  • confused...so you cant create a 10km buffer? – Ger Mar 5 '14 at 22:21
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    yes, bradhards is correct, if you do a 10km buffer on your county boundaries, a point in polygon analysis should give you the amount of points within 10km :) Good luck! – Phil Jones Mar 5 '14 at 22:24
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Not to steal thunder here but yes do what the above said, create a buffer of 10Km for your borders. I would suggest checking the box to allow for a single polygon (disolve buffers)

Once you have this layer created carry out a spatial query with spatial query under vector. Select all points within the buffer.

Then the option is to save as selection as new layer or just look at the attribute table and it will say how many selected.

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