Coordinates on a surface in which all geodesic lines are expressed by linear equations. Surfaces on which the introduction of Beltrami coordinates is possible are said to be projective (projective transformations of such surfaces convert geodesics into geodesics). So called after E. Beltrami, who studied such surfaces in 1866.

How to Cite This Entry:
Beltrami coordinates. E.V. Shikin (originator), Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Beltrami_coordinates&oldid=16573
This text originally appeared in Encyclopedia of Mathematics - ISBN 1402006098