Geographic reference system in project


Here is my question:
What is the geographic reference system used for the project function in GMT (and pyGMT)?

WGS84 or another …

Calculations of specific great-circle and geodesic distances or for back-azimuths or azimuths are better done using mapproject as project is strictly spherical (

Thank you for reply. In fact, I have to convert a script using project from GMT using project from pyGMT (to keep the same results). And by the way, I was wondering about the reference system used by default for these functions.

Since it is spherical, it is the WGS-84 sphere with radius 6371008.771

Thank you!