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Peter Van Oosterom - One of the best experts on this subject based on the ideXlab platform.

  • Constrained Set-up of the tGAP structure for progressive vector data transfer
    Computers & Geosciences, 2009
    Co-Authors: Jan-henrik Haunert, Arta Dilo, Peter Van Oosterom
    Abstract:

    A promising approach to submit a vector map from a server to a mobile client is to send a coarse representation first, which then is incrementally refined. We consider the problem of defining a sequence of such increments for areas of different land-cover classes in a planar partition. In order to submit well-generalised dataSets, we propose a method of two stages: First, we create a generalised representation from a detailed dataSet, using an optimisation approach that satisfies certain cartographic constraints. Second, we define a sequence of basic merge and simplification operations that transforms the most detailed dataSet gradually into the generalised dataSet. The obtained sequence of gradual transformations is stored without geometrical redundancy in a structure that builds up on the previously developed tGAP (topological Generalised Area Partitioning) structure. This structure and the algorithm for intermediate levels of detail (LoD) have been implemented in an object-relational database and tested for land-cover data from the official German topographic dataSet ATKIS at scale 1:50000 to the target scale 1:250000. Results of these tests allow us to conclude that the data at lowest LoD and at intermediate LoDs is well generalised. Applying specialised heuristics the applied optimisation method copes with large dataSets; the tGAP structure allows users to efficiently query and retrieve a dataSet at a specified LoD. Data are sent progressively from the server to the client: First a coarse representation is sent, which is refined until the requested LoD is reached.

Van Oosterompeter - One of the best experts on this subject based on the ideXlab platform.

Jan-henrik Haunert - One of the best experts on this subject based on the ideXlab platform.

  • Constrained Set-up of the tGAP structure for progressive vector data transfer
    Computers & Geosciences, 2009
    Co-Authors: Jan-henrik Haunert, Arta Dilo, Peter Van Oosterom
    Abstract:

    A promising approach to submit a vector map from a server to a mobile client is to send a coarse representation first, which then is incrementally refined. We consider the problem of defining a sequence of such increments for areas of different land-cover classes in a planar partition. In order to submit well-generalised dataSets, we propose a method of two stages: First, we create a generalised representation from a detailed dataSet, using an optimisation approach that satisfies certain cartographic constraints. Second, we define a sequence of basic merge and simplification operations that transforms the most detailed dataSet gradually into the generalised dataSet. The obtained sequence of gradual transformations is stored without geometrical redundancy in a structure that builds up on the previously developed tGAP (topological Generalised Area Partitioning) structure. This structure and the algorithm for intermediate levels of detail (LoD) have been implemented in an object-relational database and tested for land-cover data from the official German topographic dataSet ATKIS at scale 1:50000 to the target scale 1:250000. Results of these tests allow us to conclude that the data at lowest LoD and at intermediate LoDs is well generalised. Applying specialised heuristics the applied optimisation method copes with large dataSets; the tGAP structure allows users to efficiently query and retrieve a dataSet at a specified LoD. Data are sent progressively from the server to the client: First a coarse representation is sent, which is refined until the requested LoD is reached.

C. R. Chen - One of the best experts on this subject based on the ideXlab platform.

Haunertjan-henrik - One of the best experts on this subject based on the ideXlab platform.