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For my thesis I'm modeling the identification of recreation areas. Therefore, there has been a survey where people were asked to specify where they recreate. They had to indicate this place on a map and give a radius. Now I have to analyse which areas were most visited, and afterwards use the data to give a weighted rating with the travel distance.

So, I use QGIS to Buffer the data points by using the given radius. Now, I want to calculate for every point in the country how many times it was visited.

Any thoughts how to do this in QGIS?

  • Welcome as a contributor :-) Could you please clarify the geographical scope of your survey? It seems like you ask people where they recreate. Then you want to use the data to calculate how many times (per person?) it was visited. Sounds like you are stretching the use of your data a little too far. – ragnvald Mar 24 '15 at 14:40
  • the goal of my research is actually the training of a bayesian belief network to identify recreation areas. This would be the validation data. The frequency (how many persons) of visiting defines whether it's suitable as a recreation area or not. So, the data as a tool to learn which characteristics in an area are important for recreation. – Quinten Cormenier Mar 24 '15 at 15:13
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You could use the Intersect tool (Vector > Geoprocessing Tools > Intersect) on the buffers and then to find the number of intersections it would simply be the total number of attributes - the number of points.

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Here's a blog post by Paul Ramsey about doing this in PostGIS, perhaps a worthy venture:

http://boundlessgeo.com/2014/10/postgis-training-creating-overlays/

Summed up with this note:

Now we have a single coverage of the area, where each polygon knows how much overlap contributed to it. Ironically, when visualized using the coverage count as a variable in the color ramp, it looks a lot like the original image, which was created with a simple transparency effect. However, the point here is that we’ve created new data, in the count attribute of the new polygon layer.

enter image description here

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