a. 大地测量学的

[ adj ]
of or relating to or determined by geodesy
<adj.pert>

Geodetic \Ge`o*det"ic\, Geodetical \Ge`o*det"ic*al\, a.
Of or pertaining to geodesy; obtained or determined by the
operations of geodesy; engaged in geodesy; geodesic; as,
geodetic surveying; geodetic observers.

{Geodetic line} or {Geodetic curve}, the shortest line that
can be drawn between two points on the elipsoidal surface
of the earth; a curve drawn on any given surface so that
the osculating plane of the curve at every point shall
contain the normal to the surface; the minimum line that
can be drawn on any surface between any two points.