Timz From United States of America, joined Sep 1999, 6796 posts, RR: 7
Reply 1, posted (10 years 1 week 5 days 15 hours ago) and read 2357 times:
"GCM uses gnomonic projection for calculation itself"?
Dunno what this means. It calculates the geodesic distance, probably using Vincenty's formulas or something similar. It uses the wrong spheroid, so it can be off by a fraction of a kilometer, but the formulas are probably correct.