Examples on kohonen self organizing maps Is there a simple example to start with for using kohonen 1.1.2 or is it only the test file that will be the reference?
There are alternative solutions for self organizing maps.

Best of them I found pymvpa where the example is easy to read and understand. It is also maintained quite activately as you can see from their Github.

I tried to run the kohonen 1.1.2 test file, but it did not run after two days of trying. So, let's have a try for the another solution.

To run pyMVPA example som.py, you have to do the following (at least):

1 install some pre-requisites: at least numpy, scipy, nibabel and swig to be able to run setup.py
2 run the commands: 
   python setup.py build
   python setup.py install
3 modify example under doc/examples (som.py) to have 
 import matplotlib.pyplot as pl
4 run command:
   python som.py


Note that this works only in python 2, not python3 can be used as command.