Viewshed Computation Based on LOS Scanning

Visibility computation plays an important role in characteristics analysis and visualization of terrain surface. Firstly, we define the lines of sight in which each line is associated with viewpoint and target point on terrain with its own height. Then the vector cross product method is used to determine the visible points on this line of sight and invisible points in profile section. The paper develops the radial LOS scanning method to calculate the viewshed of viewpoint, and discusses effects with different scanning angle step in time complexity and viewshed results. The algorithm based on scanning LOS gives attentions to time-consuming and visibility approximation.