Papers by Keyword: Spatial Index

Abstract: GML is the encoding specification of geospatial data, more and more geospatial data are represented in GML documents. It’s efficient to use database technologies to manage and maintain the geospatial data described by GML. The index in a database can help to locate the tuples for a query. In order to query GML data efficiently, appropriate index structure should be designed. In this paper, a method to build path index for the GML document is proposed based on its storage schema. The path index records the sequences and levels of elements in the GML document. Tuples stored in tables can be quickly located for a query with the path index, and the structure information recorded in the path index can help to reconstruct the GML document.

Abstract: Laser point set has a massive quantity of data, which not only increases system load, but greatly reduces the follow-up processing efficiency as well. Considering the difficulty of mass point cloud data organization and management, grid index of point cloud data based on the decimal linear quadtree is proposed in this paper, point cloud data is segmented and encoded by means of linear quadtree based on decimal system, which will be stored in SQL Server, then, we can block and index point cloud in terms of Morton code or rectangular region, combine with the advantages of both spatial index and database to manage point cloud efficiently and safely. The results show that the proposed method ideally solves the problem of point cloud data organization and management.

Abstract: A continuous window query is an important class of spatial queries for location-based services. It retrieves spatial objects in a fixed window region of every point on a line segment and indicates the valid segments of them. In this paper, we focus on continuous window queries in wireless data broadcast systems. Since the query result of the continuous window queries has the spatial locality, providing neighbor information of spatial objects can guide clients to efficiently retrieve related objects. Therefore, we propose a neighbor-index method to efficiently support the continuous window queries in wireless data broadcast systems. The proposed method interleaves the neighbor information between spatial objects to guide mobile clients to quickly retrieve the answered objects and save the power consumption of the mobile devices. Experimental results show that our method outperforms the distributed indexing.

Abstract: This paper researched combining K-Means algorithm with method of spatial index in spatial database, and analyzed mainly research results of spatial index technology based on K-Means algorithm and their technical scheme. Finally, research trend of combining clustering and spatial index was proposed.

Abstract: In view of open-pit mine complex special terrain, to improved method of constructing triangulated irregular net and combined with the extended boundary, that can remission the phenomenon that steps were flattened and the problem of inefficiency mining area model update. Using constrained triangulated irregular net once generation algorithm, through extraction of spatial data, establish topological relationships and spatial indexing, eventually build a constraints of triangulated irregular net within the boundary constraint line. Combining extended boundary with the triangulated irregular net generated algorithm, can realize the establishment partial model as well as partial and overall model splicing. Thus enhanced the efficiency of the mining area overall model updating.

Abstract: Up to now, the main research in china about Chang'e satellite and data sent by it is about rail orbit determination and data use, but the study concerning the Lunar Virtual Reality Structure has not appear. Based on Lunar DEM and lunar image having been done, with Super3D Editor as a platform, lunar three-dimensional virtual operating system has been completed. This paper mainly introduces the coordinate transformation, the construction of three-dimensional model and model spatial index, and provides better technology for the information extraction.

Abstract: Vehicle navigation system (VNS) is a world acknowledged efficient way of solving the urban traffic problem, and road network database is one of the core component parts in the system. In order to improve performance of VNS, this paper conducts a research on data organization technique of road network, and proposes a novel data model of road network, which includes spatial index and topology structure. Firstly, some common spatial index structures, such as regular grid index, R-tree index and quad-tree index, are studied, and a novel spatial index structure based on “hierarchical quad-tree and R-tree” index of two ranks is proposed. This structure can greatly reduce the access time of map data and raise index performance. Secondly, a topology model of road network based on arc-relation is presented, which can effectively solve turn penalty problems in the conventional topology model based on vertex-relation and represent real road network. Thirdly, a real topology storage structure using adjacency list is designed and a corresponding creating algorithm is put forward. Finally, the tests on the practical system prove that the proposed model effectively support kinds of data-processing and greatly raise the performance of the system.

Abstract: This paper presents a new spatial index structure - cache quadtree. Cache quadtree combined with the advantages of spatial indexing and caching. According to the characteristics of spatial data, query uses the previous query results as much as possible, only the necessary queries are performed on the server. Meanwhile, full use of query results in the cache tree; reduce the server's query and its query range. Our paper gives the cache quadtree structure and the key algorithm in detail.

Abstract: As embedded and mobile devices application development and many micro-computing devices need to run the e-chart system. The tree spatial index structures can efficiently organize and retrieve spatial data. This paper discusses the index to organize and retrieve e-chart data through the quadtree. We discussed the electronic chart in the two typical quadtree on the index structure, and give the comparison and analysis of experimental data.