Quite new to using GIS and have a (probably very simple) question.

I want to see if there is a greater occurrence of a species around a certain feature. i.e. is there a greater density of a species occuring within 50 metres of a river. I have gotten as far as creating the buffer around the feature, how do I analyse the points that occur within the buffer?

closed as too broad by underdark Feb 22 at 9:19

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    Please define "likelihood". Are you looking for a statistical approach? Or do you just want to compute the point density inside and outside the river buffer? – underdark Feb 10 '17 at 13:32
  • Apologies about that. At the moment computing the point density inside and outside the buffer would be sufficient. – R. Cooney Feb 10 '17 at 13:36
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    Depending on what you are trying to find out, an alternative approach might be to calculate the distance to the nearest feature of interest. This would allow for a broader range of statistics to be calculated. – George of all trades Feb 10 '17 at 13:39

Assuming you are dealing with vector maps. If you want to find out the density of points inside the buffer, you can use the 'Count points in polygon' or 'Count points in polygon(weighted)' function for obtaining the number of points occurring in the buffer polygon.

You can find these algorithms in the Processing toolbox under QGIS geoalgorithms > Vector analysis tools


I don't know wich format you are using but guessing you are dealing with vector you could just perform an overlay operation to catch all the point within your buffer, from there you can do whatever computation needs on your dataset

hope it helps

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