1. You will need to import numpy and matplotlib import matplotlib.pyplot as plt #python plotting library import numpy as np #numpy library 2. you need to make a numpy array to use as a 2D map array gMap = np.zeros((gWidth,gHeight)) # zero out map initially gWidth and gHeight are dimensions of the array 3. You can access the numpy array as you would expect, e.g. gMap[ix][iy] = gMap[ix][iy] +1 where ix and iy are the two integer indices 4. In the shutdown callback, you can plot the map as follows plt.pcolor(gMap) plt.show() This will bring up a dialog box with a false color image of the map. There is a button on the dialog box to save the image if you want. You need to kill the dialog box before the program will end.