| Abstract: | In this paper, we present the graphics processing unit (GPU)‐based parallel implementation of visibility calculation from multiple viewpoints on raster terrain grids. Two levels of parallelism are introduced in the GPU kernels — parallel traversal of visibility rays from a single viewpoint and parallel processing of viewpoints. The obtained visibility maps are combined in parallel using the selected logical operator. A comparison with multi‐threaded CPU implementation is performed to establish the expected speed‐ups of viewshed construction when the source and destination types are sets of scattered locations, paths, or regions. The results demonstrate that using the GPU, the acceleration of an order of magnitude can be achieved on average with both point sampling and bilinear filtering of the elevation map. Copyright © 2011 John Wiley & Sons, Ltd. |
