The area we are using for this tutorial looks like this when rendered using COALA.

No crime data are requested or rendered as the unchecked "Render Crimes" checkbox is unchecked.

To simply show the locations where any kind of crimes happen, you can use the settings shown below.

To have all crimes in the areas rendered and organized in a "heatmap" style, enable the "Render Crimes" checkbox along with "Force Render All Crimes".

The area we are using has so many crime instances that the heatmap is covered in red, which represents a high crime occurrence.

This rendered heatmap uses the "Heat Map Type" flat to be able to see the exact points where crimes are taking place.

By setting the "Crime Types" in the "Crime Types to Display" to one specific type, the visualization becomes easier to understand.

In the following picture, only crimes categorized as "THEFT" are considered for rendering.

This image visualizes the heatmap way better: In denser places there are red data representations that smoothly turn to yellow and green to represent lower density.

By using "BURGLARY BREAKING AND ENTERING" for crimes to display, we get an even better visualization.

Setting the "Heat Map Type" to "Pillar" results in the following representation.