Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    On sorting triangles in a delaunay tessellation (1991)
    Springer
    Algorithmica 6 (1991), S. 522-532 
    Details
    ISSN: 1432-0541
    Keywords: Delaunay triangulation ; Sorting ; Visibility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract In a two-dimensional Delaunay-triangulated domain, there exists a partial ordering of the triangles (with respect to a vertex) that is consistent with the two-dimensional visibility of the triangles from that vertex. An equivalent statement is that a polygon that is star-shaped with respect to a given vertex can be extended, one triangle at a time, until it includes the entire domain. Arbitrary planar triangulations do not possess this useful property which allows incremental processing of the triangles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01759057
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Horizon computation on a hierarchical triangulated terrain model (1995)
    Springer
    The visual computer 11 (1995), S. 134-149 
    Details
    ISSN: 1432-2315
    Keywords: Key words: Digital terrain models ; Hierarchical models ; Visibility ; Dynamic algorithms ; Randomized algorithms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01898599
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Multiresolution models for topographic surface description (1996)
    Springer
    The visual computer 12 (1996), S. 317-345 
    Details
    ISSN: 1432-2315
    Keywords: Multiresolution surface representation ; Hierarchical data structures ; Terrain models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Multiresolution terrain models describe a topographic surface at various levels of resolution. Besides providing a data compression mechanism for dense topographic data, such models enable us to analyze and visualize surfaces at a variable resolution. This paper provides a critical survey of multiresolution terrain models. Formal definitions of hierarchical and pyramidal models are presented. Multiresolution models proposed in the literature (namely, surface quadtree, restricted quadtree, quaternary triangulation, ternary triangulation, adaptive hierarchical triangulation, hierarchical Delaunay triangulation, and Delaunay pyramid) are described and discussed within such frameworks. Construction algorithms for all such models are given, together with an analysis of their time and space complexities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01782231
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Surface representations based on triangular grids (1987)
    Springer
    The visual computer 3 (1987), S. 27-50 
    Details
    ISSN: 1432-2315
    Keywords: Triangulation ; Surface models ; Data structures ; Graphs ; Trees ; Algorithms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The problem of representing 2 1/2 dimensional surfaces defined at a set of randomly located points by means of triangular grids is considered. Such representations approximate a surface as a network of planar, triangular faces with vertices at the data points. In the paper we describe different models and data structures for encoding triangular grids. Since Delaunay triangulation provides a common basis for many models of 2 1/2 D surfaces, we review its basic properties and we describe the most important approaches to its construction. Hierarchical surface models are also presented, which are based on nested triangulations of the surface domain and provide variable resolution surface representations. An algorithm is described for building a hierarchical description of a nested triangulation at different levels of abstraction. Finally, the 3D surface reconstruction problem is briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02153649
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Horizon computation on a hierarchical triangulated terrain model (1995)
    Springer
    The visual computer 11 (1995), S. 134-149 
    Details
    ISSN: 1432-2315
    Keywords: Digital terrain models ; Hierarchical models ; Visibility ; Dynamic algorithms ; Randomized algorithms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Hierarchical terrain models describe a topographic surface at different levels of detail, thus providing a multiresolution surface representation as well as a data compression mechanism. We consider the horizon computation problem on a hierarchical polyhedral terrain (in particular, on a hierarchical triangulated irregular network), which involves extracting the horizon of a viewpoint at a given resolution and updating it as the resolution increases. We present an overview of horizon computation algorithms on a nonhierarchical polyhedral terrain. We extend such algorithms to the hierarchical case by describing a method which extracts the terrain edges at a given resolution, and proposing a randomized algorithm for dynamically updating a horizon under insertions and deletions of terain edges
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01898599
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Multiresolution models for topographic surface description (1996)
    Springer
    The visual computer 12 (1996), S. 317-345 
    Details
    ISSN: 1432-2315
    Keywords: Key words: Multiresolution surface representation ; Hierarchical data structures ; Terrain models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01782231
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Two data structures for building tetrahedralizations (1990)
    Springer
    The visual computer 6 (1990), S. 266-283 
    Details
    ISSN: 1432-2315
    Keywords: Solid modeling ; Decomposition models ; Tetrahedralization ; Delaunay triangulation ; Algorithms and data structures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract A polyhedral decomposition can be unambiguously described as the collection of four primitive elements (i.e., polyhedra, facets, edges, and vertices) plus their mutual adjacency relations. We consider here the problem of representing a specific kind of polyhedral decomposition, i.e., a tetrahedralization. We describe two different representations for a tetrahedralization. The first one can only model polyhedral decompositions with tetrahedral cells, while the second one is suitable for describing any partition of a volume into polyhedral cells with triangular facets. We present two sets of primitive Euler operators, which build and manipulate such representations while maintaining their topological integrity. The use of such operators is demonstrated in connection with two algorithms for building a Delaunay tetrahedralization, which show the different hedralization, which show the different uses of the two representations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01900749
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Visibility Computations on Hierarchical Triangulated Terrain Models (1997)
    Springer
    Geoinformatica 1 (1997), S. 219-250 
    Details
    ISSN: 1573-7624
    Keywords: multiresolution representations ; hierarchical terrain models ; visibility computation ; data structures and algorithms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract Hierarchical terrain models provide a multiresolution description of a topographic surface based on a nested partition of the domain. The tree-like structure of these models is an effective support to processing spatial operations. In this paper, we consider visibility computations on hierarchical terrain models based on triangular subdivisions, called Hierarchical Triangulated Irregular Networks (HTINs). We address two basic problems in visibility computation, namely determining the visibility of a query object, and computing the viewshed of a given viewpoint. We propose algorithms for performing such operations on an HTIN at variable resolution. A general drawback of hierarchical models is in the inconsistency of representations at variable resolution obtained from them, since vertical gaps may occur at edges where different resolutions meet. The algorithms proposed here avoid this undesired effect. A related, but independent, contribution of this paper is also a new algorithm for extracting a consistent terrain representation at variable resolution from an HTIN.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009708413602
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Compressing Triangulated Irregular Networks (2000)
    Springer
    Geoinformatica 4 (2000), S. 67-88 
    Details
    ISSN: 1573-7624
    Keywords: triangulated irregular networks ; geometric compression ; terrain modeling ; data structures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract We address the problem of designing compact data structures for encoding a Triangulated Irregular Network (TIN). In particular, we study the problem of compressing connectivity, i.e., the information describing the topological structure of the TIN, and we propose two new compression methods which have different purposes. The goal of the first method is to minimize the number of bits needed to encode connectivity information: it encodes each vertex once, and at most two bits of connectivity information for each edge of a TIN; algorithms for coding and decoding the corresponding bitstream are simple and efficient. A practical evaluation shows compression rates of about 4.2 bits per vertex, which are comparable with those achieved by more complex methods. The second method compresses a TIN at progressive levels of detail and it is based on a strategy which iteratively removes a vertex from a TIN according to an error-based criterion. Encoding and decoding algorithms are presented and compared with other approaches to progressive compression. Our method can encode more general types of triangulations, such as those constrained by topographic features, at the cost of a slightly longer bitstream.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009880409451
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    VARIANT: A System for Terrain Modeling at Variable Resolution (2000)
    Springer
    Geoinformatica 4 (2000), S. 287-315 
    Details
    ISSN: 1573-7624
    Keywords: terrain modeling ; multiresolution structures ; level of detail ; query operations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography
    Notes: Abstract We describe VARIANT (VAriable Resolution Interactive ANalysis of Terrain), an extensible system for processing and visualizing terrains represented through Triangulated Irregular Networks (TINs), featuring the accuracy of the representation, possibly variable over the terrain domain, as a further parameter in computation. VARIANT is based on a multiresolution terrain model, which we developed in our earlier research. Its architecture is made of a kernel, which provides primitive operations for building and querying the multiresolution model; and of application programs, which access a terrain model based on the primitives in the kernel. VARIANT directly supports basic queries (e.g., windowing, buffering, computation of elevation at a given point, or along a given line) as well as high-level operations (e.g., fly-over visualization, contour map extraction, viewshed analysis). However, the true power of VARIANT lies in the possibility of extending it with new applications that can exploit its multiresolution features in a transparent way.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009805426595
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...