Click the image to view the web map
Representation of terrain is as old as cartography itself and there remain numerous ways of creating interesting effects. Plan oblique can be traced back to the work of Xaver Imfeld in 1887 (featured in MapCarte 182). It’s an interesting technique because it uses a planimetric base (thus preserving scale in all directions across the entire map) yet represents terrain in apparent 3D. The trick is that the terrain is effectively stretched in the north/south axis such that the base of the terrain remains static and the peaks move…stretching everything in between. The technique overcomes some of the limitations we inevitably get with panoramic maps where foreshortening and occlusions are potentially problematic.
There are plenty of ways one can create a plan oblique effect using Digital Elevation Models (unless you have a preference for the hand-drawn approach like Imfeld) but the beauty of the map application developed by Buddeberg et al. is it gives the user all the tools to modify the variables that control the appearance on the fly. Azimith and inclination are basic variables to allow the creation of hillshades and 3D relief. Additionally, users can modify hyposmetric tints, the rotation and, crucially, the inclination of the viewing angle that modifies the plan oblique effect. The user controls are intuitive; the effect impressive; and the way in which the application reveals the nuance and beauty of a plan oblique representation unparalleled.