Spatial data infrastructure is the main data base of e-government, and provides spatial data even the geospatial services guarantee for e-government decision support. The traditional spatial data ...infrastructure can meet e-government for spatial data visualization and query browsing needs, but the complex spatial analysis demand of disaster assessment and other professional services, spatial data infrastructure reflected inadequate. After analyzing the relationship among SDI e-government and geospatial services, a common spatial services aggregation model is designed, this provides the ability to conflate of geoprocessing service chains dynamically Support e-government decision-making. The experiments represent lightweight spatial analysis solutions could be construct flexibly.
In the past ten years, many researchers have focused attention on developing better data structures for storing graphical information. Among the proposed data structures, the quad tree data structure ...provides a good way to organize objects on a 2-D plane. Region searches proceed at logarithmic speeds a desirable characteristic, but no previously proposed VLSI quad tree data structure distributed objects to subdivide the spatial area. This has been a major drawback for operations such as tree searching and window query. In this paper, we present a new division method to reconstruct those quad trees including the multiple storage quad tree (MSQT) and the quad list quad tree (QLQT) into nearly balanced quad tree data structures. Nearly balanced quad trees based on our new spatial division method are constructed by dynamically translating unbalanced multiple storage quad trees or unbalanced quad list quad trees into balanced structures. All benefits of the original quad tree data structures are completely retained. In addition, this method is simple and balanced quad trees memory require less than the original quad trees. Experimental results illustrate that the improvement in region queries of the presented nearly balanced quad trees to both of the QLQT and the MSQT is better than the improvement of the QLQT to the MSQT.
Environment problems are becoming the hot spots of society, and how to realize the sharing of data information and avoid the phenomenon of information isolated island is in urgent need for current ...environment protection department. This article aims to build a unified environment information sharing platform to realize information resource exchange between different systems. Departments and levels as well as horizontal and longitudinal exchange in order to simplify the difficulties of environment data management and increase the level of environment data management by integrating various applications and data resources.
According to popularization of geographic information system (GIS), temporal data management becomes very important. When GIS is used in daily work, the most frequently accessed data is the present ...data. So, the access speed on the present data should not be lowered in spatiotemporal data management. Furthermore, the past data should also be able to be restored. This paper proposes a spatio-temporal data management method based on a geographic differential script file (GDSF) method. This method records the change of map in the form of graphical operation with the time print. When an old data becomes necessary, the data is restored by applying the GDSF onto the current map data. For executing spatial retrieval fast, this paper describes a combination method of spatial data structure GBD tree and the GDSF.
This paper proposes fast initial construction methods of the GBD-tree. GDB tree has proper characteristics for management of large amount of 2 or 3 dimensional data. However, the GBD-tree needs long ...initial construction time, because no bulk insertion method as for R-tree has been proposed for the GBD-tree. This paper proposes fast initial construction method. The method requires only limited size of work space. The experimental results show the initial construction time reduces into a third or a quarter of the one-by-one insertion method. The memory efficiency and retrieval efficiency are also improved than the one-by-one insertion method.
Computing and presenting emergent crowd simulations in real time is a computationally intensive task. This intensity is mostly due to the complexity of the traversal algorithm needed for the ...interactions of all elements against each other on the basis of a proximity query. By using special data structures such as grids, and due to the parallel nature of graphics hardware, relevant previou work reduced this complexity considerably, making it possible to achieve interactive frame rates. However, existing proposals tend to be heavily bound by the maximum density of such grids, which is usually high, leading to arguably inefficient algorithms. In this article we propose the use of a fine- grained grid and accompanying data manipulation, to lead to scalable algorithmic complexity. We also implement a representative flocking boids case study, from which we ran benchmarks with more than one million simulated and rendered boids at nearly 30fps. We remark that related previous work achieved no more than 15,000 boids with interactive frame rates.
Geometric objects such as polygons, line segments, and points may have manifold relations among each other, i.e., order, adjacency, connectivity, etc., and may be stored in a database. For the design ...of the spatial data structure and in order to preserve consistency when manipulating the data, we propose a graph grammar approach. All consistent states are described by a structure graph, and the manipulation rules are given by productions where intersection problems as well as topologic properties have to be solved. By appropriately modeling the behavior of geographic data, consistency is preserved at all times. This eliminates the tedious case of recovering a geographic database after an inconsistency has been detected.
In this paper, we describe STREN, a parallel stereo renderer for fixed-location terrain rendering tasks required for the simulation of planetary exploration missions. The renderer is based on a novel ...spatial data representation, called the TANPO map. This data representation stores terrain data using a simple and compact structure and provides excellent locality for such rendering applications. Experimental results show that the renderer not only performs very well, but also scales perfectly to different numbers of processors. Examples of the rendered result is show below using the red/blue stereo display method. Click on the image to view an stereo MPEG movie (2 MBytes).
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