Developing a Faster LOS Algorithm for Faster Viewshed Generation

Abstract

The R3 viewshed algorithm is widely used in the GIS industry as it is an accurate method for viewshed generation. However, the computational speed of the R3 algorithm is slow. Other algorithms, although faster, only provide an approximation of the viewshed. So, an accurate viewshed algorithm which provides a faster result is anticipated. A faster viewshed algorithm based on R3 method has been formulated and developed in this study. The improvement is based on the process that separates shadow regions, which reduces number of intermediate points for visibility analysis.The faster viewshed algorithm has been tested and verified to confirm the improvements brought over the general viewshed algorithm. Experimental tests were carried over the geographic database of 48000 sq. km which included terrains varying from 58 m to 8000 m. The results obtained from all these tests have suggested a clear and significant gain in the computation time.