Timz From United States of America, joined Sep 1999, 6966 posts, RR: 6
Reply 1, posted (10 years 9 months 1 week 4 days 16 hours ago) and read 2547 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.