Approximating the visible region of a point on a terrain

Boaz Ben-Moshe, Paz Carmi, Matthew J. Katz

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Scopus citations

Abstract

Given a terrain T and a point p on or above it, we wish to compute the region Rp that is visible from p. We present a generic radar-like algorithm for computing an approximation of Rp. The algorithm extrapolates the visible region between two consecutive rays (emanating from p) whenever the rays are close enough; that is, whenever the difference between the sets of visible segments along the cross sections in the directions specified by the rays is below some threshold. Thus the density of the sampling by rays is sensitive to the shape of the visible region. We suggest a specific way to measure the resemblance (difference) and to extrapolate the visible region between two consecutive rays. We also present an alternative algorithm, which uses circles of increasing radii centered at p instead of rays emanating from p. Both algorithms compute a representation of the (approximated) visible region that is especially suitable for visibility from p queries. Finally, we report on the experiments that we performed with these algorithms and with their corresponding fixed versions, using a natural error measure. Our main conclusion is that the radar-like algorithm is significantly better than the others.

Original languageEnglish
Title of host publicationProceedings of the Sixth Workshop on Algorithm Engineering and Experiments and the First Workshop on Analytic Algoritms and Combinatorics
EditorsL. Arge, G.F. Italiano, R. Sedgewick
Pages120-128
Number of pages9
StatePublished - 22 Nov 2004
EventProceedings of the Sixth Workshop on Algorithm Engineering and Experiments and the First Workshop on Analytic Algorithms and Combinatorics - New Orleans, LA, United States
Duration: 10 Jan 200410 Jan 2004

Conference

ConferenceProceedings of the Sixth Workshop on Algorithm Engineering and Experiments and the First Workshop on Analytic Algorithms and Combinatorics
Country/TerritoryUnited States
CityNew Orleans, LA
Period10/01/0410/01/04

ASJC Scopus subject areas

  • General Engineering

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