DennisOSRM/Project-OSRM — pull request #596 by emiltin (2013-02-23 13:02:59+00:00)
Title: correct turn angles (and instructions) at high latitudes

solves the problem of distorted angles, and thus incorrect turn instructions, at high latitudes.

keeps the original atan() formula, but scales lat deltas by the longitudinal shortening at the C lat. only adds a single cos() call.