测地线

geodesic / a geodesic (curve)

to survey / to measure / to conjecture

-ly / structural particle: used before a verb or adjective, linking it to preceding modifying adverbial adjunct

earth / ground / field / place / land / CL:片[pian4]

earth (wire) / ground

variant of 線|线[xian4]

thread / string / wire / line / CL:條|条[tiao2],股[gu3],根[gen1] / (after a number) tier (unofficial ranking of a Chinese city)

geodesic curvature