This gives a lot of importance to small airports in small islands. Big international airports are surrounded by other smaller airports. They are associated with a tiny surface. I can not see how this representation may be of any use for airports.
This has a big influence on which routes a plane can fly. You can’t be more than a certain distance from a usable airport at any time during the flight to mitigate the risk of engine failure resulting in an off-airport landing/crash. See: https://en.m.wikipedia.org/wiki/ETOPS
