A new algorithm for viewshed computation on raster terrain

Abstract

Viewshed is a geographical area that is visible from a given location. Viewshed computation from a given point is a complex problem and plays an indispensable role in many applications of military civil engineering such as electronic warfare simulation or wireless transmittance. There are some approaches applied to analyze viewshed such as R2 (Franklin and Rays method), sweep-line (Van Krevelds method). In this paper, a new approach that increases the order of accuracy and can be easily implemented is introduced: High Level Direction (HLD). This method implements a unique radar-like algorithm to divide terrain into sectors for analysis. Compared with the other methods such as R2 or sweep-line, the advantages of this approach are in its storage approach and handling of cached data to export the final viewshed results. In contrast with the Van Krevelds method, that uses the complicated AVL trees, HLD method uses only data structured in a vector type to keep the same computational speed and export high resolution results. HLD is flexible in the selection of its accuracy and complication since a parameter that helps to balance accuracy, computational complexity, and practical requirements is used. The simulation results show that the HLD approach improves the implementation compared to other viewshed calculation methods that have the same order of accuracy.