I have been having a play around with the Heatmap (Kernel Density Estimation) tool in QGIS 3.4 and I realised that I do not really understand the output.
My understanding was that you choose the radius at which you want to analyse your point data with and the output will show you how many points can be found within a circle of chosen radius from any point in the output raster. I now know this to be wrong after looking at the results.
I have 3 points that I want to run the heatmap analysis (red circles) on and want to use a radius of 8 kilometers. I choose a pixel size of 100 (I understand the effect that varying pixels sizes can have on an output) and select the Quartic kernel shape (because it was default). Decay ratio is set to 0.
The output can be seen in the below image. I have marked the raster values along a singular radius of each circle.
What are these values telling me about that specific location in the heatmap and for a larger data set how could I make a heatmap where these values are meaningful to an audience who might not be as adept (I am clearly one of them!).