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HiVewshed: An Interactive Online Viewshed Analysis System for Multiple Observers

Viewshed analysis is a fundamental operation of most geographic information system software. The last decade has witnessed an explosion in the availability of terrain data with high resolutions. Hence, it is essential to develop efficient viewshed analysis system to process these data. This paper demonstrates the design and engineering of an interactive online viewshed analysis system named HiViewshed on massive grid terrains. HiViewshed takes advantage of hybrid parallel computing architectures with message-based and shared-memory parallelism, and it has overcome problems and deficiencies of the existing systems. The main features of the system include (a) MPI/OpenMP based parallel computing of total viewshed analysis for multiple observation points in a large region, (b) parallel DEM data access with multi-resolution strategy ensuring online analysis quality with limited bandwidth and computing resources, and (c) favorable parallel acceleration and scalability in cluster architecture. Experimental results have shown that, it can respond in an acceptable time with several hundreds of observation points simultaneously.