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I'm new to QGIS (Dufour 2.0.1) and have plotted nests as points on a googlemaps base-map and have created buffer zones around the nests. I've also plotted ponds as polygons on the same base-map. I want to know how to calculate the area of the ponds which fall within the buffer zone PER NEST.

  • Do your nest buffer zones overlap each other? If so, then in effect you want to run an intersect of ponds with each nest buffer, right? – Baltok Apr 16 '14 at 16:22
  • Yes they do overlap. I think you understand me correctly. I've already tried an intersect of the ponds layer and nests layer but i'm struggling to work out how to calculate the area of ponds PER NEST rather than included in all buffers. Thanks. – user29279 Apr 16 '14 at 16:53
  • The only way I can think of to do it is programmatically, unless you separated each nest buffer by a query or export, and ran an intersect on each iteration. Not sure how to do either of those methods in QGIS though. Hopefully, some gurus will chime in. Good luck! – Baltok Apr 16 '14 at 17:01
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Its been a while since you posted your problem, but in case you haven´t solved the problem yet, here´s my go at the issue.

Your problem is much the same as mine. I got two answers, which both, in their own different ways, solved my problem. Your nests=my map sheets and your ponds=my land use parcels. I don´t know if this functionality exists in QGIS, but OpenJump has a tool for this. And just like QGIS, it´s open source software. The only (possible) downside (if your datasets are big) is that OpenJump requires quite a bit of RAM. See the anwers on my question for instructions.

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