Optimizing line-of-sight using simplified regular terrains

Alderson, Troy; Samavati, Faramarz

doi:10.1007/s00371-014-0936-3

Cited by 8 publications

(2 citation statements)

References 20 publications

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“…A special case of ray shooting can be used to compute point-to-point visibility in 2D and 3D [14]. Many visibility analyses in GIS are available for 2.5D data based on raster [18][19][20][21] or TIN structure [22][23][24]. In these cases, for the line-of-sight computation, several restrictions can be observed: (1) observer and target must be on or above the surface; and (2) all participating data layers must be preprocessed into a single digital surface model.…”

Section: D Line-of-sight Computationmentioning

confidence: 99%

3D WebGIS: From Visualization to Analysis. An Efficient Browser-Based 3D Line-of-Sight Analysis

Auer

Zipf

2018

IJGI

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3D WebGIS systems have been mentioned in the literature almost since the beginning of the graphical web era in the late 1990s. The potential use of 3D WebGIS is linked to a wide range of scientific and application domains, such as planning, controlling, tracking or simulation in crisis management, military mission planning, urban information systems, energy facilities or cultural heritage management, just to name a few. Nevertheless, many applications or research prototypes entitled as 3D WebGIS or similar are mainly about 3D visualization of GIS data or the visualization of analysis results, rather than about performing the 3D analysis itself online. This research paper aims to step forward into the direction of web-based 3D geospatial analysis. It describes how to overcome speed and memory restrictions in web-based data management by adapting optimization strategies, developed earlier for web-based 3D visualization. These are applied in a holistic way in the context of a fully 3D line-of-sight computation over several layers with split (tiled) and unsplit (static) data sources. Different optimization approaches are combined and evaluated to enable an efficient client side analysis and a real 3D WebGIS functionality using new web technologies such as HTML5 and WebGL.

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Section: D Line-of-sight Computationmentioning

confidence: 99%

3D WebGIS: From Visualization to Analysis. An Efficient Browser-Based 3D Line-of-Sight Analysis

Auer

Zipf

2018

IJGI

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“…In contrast, the algorithm presented in this article solves a much simpler problem but has been implemented and shown to run linearly and fast when processing very large raster datasets on small machines. Alderson and Samavati [2015] describe some techniques for speeding up line of sight algorithms. They use a terrain simplification strategy that counteracts the loss of accuracy due to simplification with some iterative methods (using residual multiresolution vectors) to try to improve the accuracy.…”

Section: Introductionmentioning

confidence: 99%

Untitled

2016

ACM Trans. Spatial Algorithms Syst.

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This article presents TILEDVS, a fast external algorithm and implementation for computing viewsheds. TILEDVS is intended for terrains that are too large for internal memory, even more than 100,000×100,000 points. It subdivides the terrain into tiles that are stored compressed on disk and then paged into memory with a custom cache data structure and least recently used algorithm. If there is sufficient available memory to store a whole row of tiles, which is easy, then this specialized data management is faster than relying on the operating system's virtual memory management. Applications of viewshed computation include siting radio transmitters, surveillance, and visual environmental impact measurement.TILEDVS runs a rotating line of sight from the observer to points on the region boundary. For each boundary point, it computes the visibility of all terrain points close to the line of sight. The running time is linear in the number of points. No terrain tile is read more than twice. TILEDVS is very fast, for instance, processing a 104,000×104,000 terrain on a modest computer with only 512MB of RAM took only 1 1 2 hours. On large datasets, TILEDVS was several times faster than competing algorithms, such as the ones included in GRASS. The source code of TILEDVS is freely available for nonprofit researchers to study, use, and extend.A preliminary version of this algorithm appeared in a four-page ACM SIGSPATIAL GIS 2012 conference paper, "More Efficient Terrain Viewshed Computation on Massive Datasets Using External Memory." This more detailed version adds the fast lossless compression stage that reduces the time by 30% to 40%, and many more experiments and comparisons.

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A draw call-oriented approach for visibility of static and dynamic scenes with large number of triangles

Serpa

Rodriguês

2018

Vis Comput

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Optimizing line-of-sight using simplified regular terrains

Cited by 8 publications

References 20 publications

3D WebGIS: From Visualization to Analysis. An Efficient Browser-Based 3D Line-of-Sight Analysis

3D WebGIS: From Visualization to Analysis. An Efficient Browser-Based 3D Line-of-Sight Analysis

Untitled

A draw call-oriented approach for visibility of static and dynamic scenes with large number of triangles

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