As various types of information are being created through the recent technical developments in, and use of, smart devices, it is becoming increasingly important to manage spatial information, which is the foundation f...
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ISBN:
(数字)9783030172466
ISBN:
(纸本)9783030172459;9783030172466
As various types of information are being created through the recent technical developments in, and use of, smart devices, it is becoming increasingly important to manage spatial information, which is the foundation for utilizing information. This study defines the characteristics of spatial information, which can be used in the future, and proposes a 3d geospatial grid system (3dGGS) to manage spatial information. Based on a literature review, the characteristics of spatial information, which will be required in the future, are examined. Thus, the concept and characteristics of 3dGGS are presented, based upon which the application scope and rules of 3dGGS are set. In addition, geographic information systems developed by the Rep. of Korea and other countries are analyzed, and an architecture and framework through which 3dGGS can be implemented are presented. Finally, the results of this study are summarized, and areas of future works are introduced.
In the next few years, 3ddata is expected to be an intrinsic part of geospatialdata. However, issues on 3d spatial data management are still in the research stage. One of the issues is performance deterioration duri...
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ISBN:
(纸本)9783319121819;9783319121802
In the next few years, 3ddata is expected to be an intrinsic part of geospatialdata. However, issues on 3d spatial data management are still in the research stage. One of the issues is performance deterioration during 3ddata retrieval. Thus, a practical 3d index structure is required for efficient data constellation. due to its reputation and simplicity, R-Tree has been received increasing attention for 3d geospatialdatabase management. However, the transition of its structure from 2d to 3d had caused a serious overlapping among nodes. Overlapping nodes also occur during splitting operation of the overflown node N of M + 1 entry. Splitting operation is the most critical process of 3d R-Tree. The produced tree should satisfy the condition of minimal overlap and minimal volume coverage in addition with preserving a minimal tree height. Based on these concerns, in this paper, we proposed a crisp clustering algorithm for the construction of a 3d R-Tree. Several datasets are tested using the proposed method and the percentage of the overlapping parallelepipeds and volume coverage are computed and compared with the original R-Tree and other practical approaches. The experiments demonstrated in this research substantiated that the proposed crisp clustering is capable to preserve minimal overlap, coverage and tree height, which is advantageous for 3d geospatialdata implementations. Another advantage of this approachis that the properties of this crisp clustering algorithm are analogous to the original R-Tree splitting procedure, which makes the implementation of this approach straightforward.
The advantages of three dimensional (3d) city models can be seen in various applications including photogrammetry, urban and regional planning, computer games, etc.. They expand the visualization and analysis capabili...
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The advantages of three dimensional (3d) city models can be seen in various applications including photogrammetry, urban and regional planning, computer games, etc.. They expand the visualization and analysis capabilities of Geographic Information Systems on cities, and they can be developed using web standards. However, these 3d city models consume much more storage compared to two dimensional (2d) spatialdata. They involve extra geometrical and topological information together with semantic data. Without a proper spatialdata clustering method and its corresponding spatialdata access method, retrieving portions of and especially searching these 3d city models, will not be done optimally. Even though current developments are based on an open data model allotted by the Open Geospatial Consortium (OGC) called CityGML, its XML-based structure makes it challenging to cluster the 3d urban objects. In this research, we propose an opponent data constellation technique of space-filling curves (3d Hilbert curves) for 3d city model data representation. Unlike previous methods, that try to project 3d or n-dimensional datadown to 2d or 3d using Principal Component Analysis (PCA) or Hilbert mappings, in this research, we extend the Hilbert space-filling curve to one higher dimension for 3d city model data implementations. The query performance was tested using a CityGML dataset of 1,000 building blocks and the results are presented in this paper. The advantages of implementing space-filling curves in 3d city modeling will improve data retrieval time by means of optimized3d adjacency, nearest neighbor information and3d indexing. The Hilbert mapping, which maps a sub-interval of the [0, 1] interval to the corresponding portion of the d-dimensional Hilbert's curve, preserves the Lebesgue measure and is Lipschitz continuous. depending on the applications, several alternatives are possible in order to cluster spatialdata together in the thirddimension compared to its clusteri
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