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?