3D Maps with Progressive Bending

The progressive projection offers a number of advantages when designing a 3D map compared to the standard central perspective projection. Many panorama painters, such as Heinrich C. Berann, prefer the view from lowlands to highlands, depicting a horizon with high mountainous terrain in the map background. In standard central perspective projection, the background of the 3D map is simply cut off where the terrain ends, without conveying the impression of a real horizon. This undesirable cut-off line is the result of looking at the terrain from a steep viewing angle.
When a central perspective projection with a flat viewing angle is chosen, a horizon is formed by mountains in the background, but unfortunately, a uniform flat viewing angle flattens the entire terrain and as a result compresses the foreground. The progressive projection solves this problem by progressively varying the viewing angle from steep in the foreground to flat in the background.