The notebook shows how to make digital colour images by combining data layers, using two techniques:
1) set 3 layers as the RGB channels;
2) colourize any number of layers and blend them.
Both techniques are commonly used for scientific visualization, in particular to create images from astronomical data.

The code for making the images is found in combine.py.
Additional code for making mock data is found in mock.py.

A rendered version of the notebook can be seen on nbviewer.