Advanced visibility analyses and visibility evaluation using eye-tracking

The aim of this project was to create a cumulative visibility raster (find out viewshed information for every point) and characterize visibility over the entire terrain surface. Creation of cumulative visibility raster is very time consuming and hardware-demanding. Within high-performance computation, the analysis was calculated by parallel processing. Mallorca was chosen as an area of interest because it has sharp natural and elevation borders, so it is suitable for testing of advanced visibility analyses. After the creation of the cumulative visibility raster, it is possible to evaluate the terrain with many visibility characteristics, for example cumulative visibility, slope of cumulative visibility, or present target visible. A question exists if it is necessary to compute visibility analyses in all cases - even in the simplest ones. Are people not able to see what is visible and what is not, just from the representation of the terrain? The paper shows early results of eye-tracking evaluation of two different types of visualization of landscape - classical orthogonal maps and three-dimensional (3D) perspective views. It was found that for better perception of the terrain and deriving information whether the place is visible or not, 3D view is more appropriate.