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I have a dataset with approx 1250 geolocated points - approx 150 are cases of a disease and the rest are controls. My area of interest is around 20km by 20km with wide variation in population density. I would like to display prevalance (cases/(cases+controls)) as either a kernel density layer or using contours. I would like to use a 3km Gaussian kernel.

Are there plug-ins that can do this?

I couldn't see how to do this in Heatmap.

  • 2
    Try processing tool SAGA - Grid - Gridding - Kernel density estimation. – user30184 Nov 16 '15 at 16:00
  • Looks good, do you know if that is available on Mac? I have QGIS 2.2 installed and can't see it in the list of available plugins. – user62435 Nov 16 '15 at 16:19
  • I am on Windows and thought that SAGA tools were disappeared until I noticed that they appear in "Advanced interface". Have you selected that in the processing tools? – user30184 Nov 16 '15 at 16:45
  • Found it. However, I get an error when I run it (Oooops! The following output layers could not be open Grid: /var/folders/k0/3n1q2ck13v736j6tr5ckftlc0000gn/T/processing/c1cadb6d0e094792ad992cd3ccbae923/USERGRID.tif). The error comes after the log says 'Loading resulting layers'. I can't see any help file for the tool? Perhaps I am not inputting things correctly? – user62435 Nov 17 '15 at 6:57
  • Seems like the tool is writing (trying to write?) a temporary output file to that weird location at /var/folders.... but fails. Try if changing the result directory from Processing - Settings helps. I have only used that kernel density tool directly with SAGA but never through QGIS. – user30184 Nov 17 '15 at 10:05

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