Creating a heat map

A heat map is used to show the geographic clustering of data using a raster image that shows density. The clustering can also be weighed using a field in the data to not only show geographic density but also an intensity factor. In this recipe, we'll use earthquake point data to create a heat map of the impact of an earthquake and weigh the clustering by the earthquake's magnitude.

Getting ready

This recipe requires no preparation.

How to do it...

We will build a map with a worldwide base layer of countries and earthquake locations, both in GeoJSON. Next, we'll run the SAGA kernel density estimation algorithm to produce the heat map image. We'll create a layer from the output, add a color shader to it, and add it to the map.

To do this, we need to perform the following steps:

1. First, we'll import the Python libraries that we'll need in the Python console:

   from PyQt4.QtCore import *
   from PyQt4.QtGui import *
   import processing
   

2. Next, using the following...