Introduction to algorithms
Cache Oblivious Distribution Sweeping
ICALP '02 Proceedings of the 29th International Colloquium on Automata, Languages and Programming
ESA '95 Proceedings of the Third Annual European Symposium on Algorithms
External-Memory Algorithms with Applications in GIS
Algorithmic Foundations of Geographic Information Systems, this book originated from the CISM Advanced School on the Algorithmic Foundations of Geographic Information Systems
FOCS '99 Proceedings of the 40th Annual Symposium on Foundations of Computer Science
I/O-Efficient Algorithms for Problems on Grid-Based Terrains
Journal of Experimental Algorithmics (JEA)
External memory graph algorithms and applications to geographic information systems
External memory graph algorithms and applications to geographic information systems
Guarding a terrain by two watchtowers
SCG '05 Proceedings of the twenty-first annual symposium on Computational geometry
A constant-factor approximation algorithm for optimal terrain guarding
SODA '05 Proceedings of the sixteenth annual ACM-SIAM symposium on Discrete algorithms
Engineering a cache-oblivious sorting algorithm
Journal of Experimental Algorithmics (JEA)
STXXL: standard template library for XXL data sets
ESA'05 Proceedings of the 13th annual European conference on Algorithms
Improved visibility computation on massive grid terrains
Proceedings of the 17th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems
Fast prediction of scattering in mountainous terrain using commonly visible surfaces
Sarnoff'10 Proceedings of the 33rd IEEE conference on Sarnoff
Viewsheds on terrains in external memory
SIGSPATIAL Special
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Given an arbitrary viewpoint v and a terrain, the visibility map or viewshed of v is the set of points in the terrain that are visible from v. In this article we consider the problem of computing the viewshed of a point on a very large grid terrain in external memory. We describe algorithms for this problem in the cache-aware and cache-oblivious models, together with an implementation and an experimental evaluation. Our algorithms are a novel application of the distribution sweeping technique and use O(sort(n)) I/Os, where sort(n) is the complexity of sorting n items of data in the I/O-model. The experimental results demonstrate that our algorithm scales up and performs significantly better than the traditional internal-memory plane sweep algorithm and can compute visibility for terrains of 1.1 billion points in less than 4 hours on a low-cost machine compared to more than 32 hours with the internal-memory algorithm.