Remarks:
1) images are comprised of grids e.g. 1x1 km
2) magnitudes (grid colors) are important
3) form/shape of clusters are important
4) maps can be binary
5) python based clustering is favored
6) we are aware of Dr. Rodger B. Grayson's papers like http://www.sciencedirect.com/science/article/pii/S0309170804001575