Our current situation is that we have around 40,000 geolocated settlements across Africa, and each is located on a detailed road network shapefile. We would like to calculate the shortest distances by road from each settlement to every other settlement (i.e. creating a huge 40,000 x 40,000 Origin-Destination matrix of distances) - we have a methodology to do this for smaller datasets within GIS software, but are held back by memory limitations for such a large operation. Hence, we were interested to explore your methods before we consider developing our own solutions. Do you have any advice or suggestions on proceeding with this please ?