Add on package for Addi. Has no use without Addi. Install Addi 1. 8 or later before this. Contains functions: azimuth. Calculates the great circle azimuth from a point 1 to a point 2. Y. Distance. Calculates the distance between PT1 and PT2. Reckon. Compute the coordinates of the end-point of a displacement on a sphere. Rad2deg.