0

I use QGIS 2.18.14 I import csv file with hits on a certain area. I then create a simple indicative heatmap (properties > heatmap).

Can I add contour lines to this heatmap and if yes, how?

I also put a vector grid on these hits > count points in polygon and then via properties > graduated based number of hits per square.

Can I add contour lines to this square based heat map and if yes, how?

Improve this question
  • Welcome to gis.stackexchange! Please note that a good question on this site is expected to show some degree of research on your part, i.e. what you have tried and - if applicable - code so far. For more info, you can check our faq. – underdark♦ Feb 1 '18 at 20:27
5

It is possible to simply add contours to a raster image via the Processing Toolbox -> Contour (Under GDAL Extraction). Here is an example: Input Raster Image created from point layer using QGIS HeatMap Plugin : enter image description here

After running GDAL Contour (Interval between contour lines = 1, keep the rest as is):

enter image description here

Improve this answer
  • Thanks! That is what I was looking for! Is there a way to make the contour lines match the categories of the heat map? – stijn geldof Jan 31 '18 at 14:48
  • Well, the heat raster layer you created contains continuous data, so the data itself does not contain any categories. The default way to control the 'categories' of the contour is the interval parameter aforementioned. However, if you'd like to override and create categories manually, you can add them under 'Additional creation parameters' and write "-fl 0.5 1 2 3 4 5 6 7 8 9", for example. – 15Step Jan 31 '18 at 15:03

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.