Tissot Indicatrix for Map Projection Distortion // Compute and visualize the 'Tissot Indicatrix' for map projections. The indicatrix characterizes projection distortion by computing scale factors, angular deformation, areal distortion, and convergence at arbitrary points. Based on the calculations shared by Bill Huber on https://gis.stackexchange.com/a/5075/482. Uses 'PROJ' for coordinate transformation and distortion factor computation. Developed using the method published in Snyder, JP (1987) doi:10.3133/pp1395.