Look-From Camera Control for 3D Terrain Maps.

We introduce three lightweight interactive camera control techniques for 3D terrain maps on touch devices based on a look-from metaphor (Discrete Look-From-At, Continuous Look-From-Forwards, and Continuous Look-From-Towards). These techniques complement traditional touch screen pan, zoom, rotate, and pitch controls allowing viewers to quickly transition between top-down, oblique, and ground-level views. We present the results of a study in which we asked participants to perform elevation comparison and line-of-sight determination tasks using each technique. Our results highlight how look-from techniques can be integrated on top of current direct manipulation navigation approaches by combining several direct manipulation operations into a single look-from operation. Additionally, they show how look-from techniques help viewers complete a variety of common and challenging map-based tasks.