Map projection distortion
Length distortion
- The ratio of map distance to geodesic distance is not constant.
- “Equidistant” map projections have a constant distance ratio in one direction (E.g.: North/South distances)
Angular distortion
- A map projection may or may not preserve angles.
- A map projection is conformal if it preserves angles.
Area distortion
- The ratio of map area to ellipsoid area may not be constant.
- “Equi-area” map projections have a constant area ratio.