An oracle-based data management method for large database in CyberCity GIS

An Oracle8i-based approach is proposed to manage the integrated databases of large CyberCity. This approach consists of threeschemes: ① a special R -tree index is designed to accelerate spatial retrieving, in which the bounding boxes of local regions have no intersection and all leaf nodes of the R -tree (geometry records ) have no repetitiont;② different data compression algorithms are adopted to compress the digital elevation models, 3D vector models and images, such as LZ77 lossless compression algorithm for compression of vector data and JPEG compression algorithms for texture images;③ in order to communicate with Oracle8i database, a CyberCity GIS spatial database engine (SDE) is designed. On the basis of this SDE prototype a case study is done.     

ARCSDE与Oracle9i Spatial空间数据转换方法研究

通过空间数据库引擎技术(SDE)可以有效地实现空间数据在数据库中的管理。但各种空间数据库引擎在储存数据格式上的不一致,都会影响各引擎相互问数据操作的效率。文中以ESRI公司的ArcSDE和Oracle公司的Oracle Spatial为例．通过分析以上两种空间数据库引擎的数据格式,解决了从ArcSDE向Oracle9i Spatial的空间数据的转换问题。     

城市GIS社会化应用中的分布式数据组织方法研究

社会化应用是城市GIS重要的发展方向,城市GIS社会化应用中对于分布于不同城市管理部门的空间数据和属性数据的管理一直是一个比较棘手的问题。本文分析了城市GIS社会化应用的内容和总体结构,提出了基于Oracle分布式数据库的数据组织方案,并对该方法进行了验证。     

电子政务空间辅助决策系统中数据库性能的优化

Oracle9i数据库系统是一个大型而复杂的运行系统,其运行效率对系统性能至关重要。本文从数据库结构、SQL语句和内存分配等三个方面对Oracle9i数据库性能的优化做了阐述,提出了一些原则和方法。     

十进制线性四叉树的点云数据格网索引方法研究

三维激光点云数据是海量三维点的集合,导致数据量庞大,组织和管理困难,不仅增加了系统负荷,而且大大降低了点云数据后续处理效率。该文针对海量点云数据的组织与管理中遇到的加载和显示效率低、建立索引困难、不能实时动态显示等问题,提出了基于十进制线性四叉树的点云数据格网索引方法,该方法用四叉树结构分割点云数据和用SQL Server数据库存储,采用Morton码或矩形区域对点云数据进行分块空间索引,结合空间索引和数据库的优势对点云数据进行高效、动态、智能管理。实验结果表明,该方法较好地解决海量点云数据的组织与管理效率低下,不能实时动态显示的问题。     

一种面向地理信息系统的空间索引方法

空间检索技术是有交地管理和操纵空间数据的一种必要手段，本文分析了目前常用的空间检索方法在地理信息系统应用上的局限性，指出了一种基于凸多边形的空间索引技术，本文首衔介绍了目前常用的几类空间索引技术及其特点，接着讨论卫面向地理信息的空间索引技术面临的基本问题，提出了基于凸多边形的空间索引结构－CP－树，并侧重分析了其空间运算算法及时空效率，最后指出了空间索引技术所存在的问题及下一步的研究方向。     

分布式空间数据库中矢量数据多级空间索引方法研究

随着网格计算、云计算等技术在地理信息领域的应用,海量空间数据的高效组织与管理成为提供各种数据和功能服务的基础,空间索引是其中的关键问题,文中在分布式空间数据库系统架构基础上,提出一种适应分布式环境下的分层+分块的矢量数据存储组织模型,设计包括矢量数据面片索引、矢量数据层索引、矢量数据块索引以及数据块内索引在内的多级空间索引。实现表明,文中设计的空间索引支持并发创建和高并发条件下的数据高效访问。     

基于MapX下GIS数据在Oracle Spatial中存储和管理

介绍了GIS空间数据和属性数据在Oracle Spatial中一体化存储的实现方法,针对MapX不能在数据库中存放注记的缺陷,提出3种解决方案并比较其优劣,对GIS的开发具有实际意义和参考价值。     

基于空间数据库的山东城镇发展水平的空间统计分析

基于GIS空间数据库,对山东省108个城镇的综合发展水平进行了空间统计分析。首先选用了反映城市综合发展水平的14项指标,并进行了主成分分析,得出反映城镇综合发展水平的综合指标,并分析了山东省各城镇的综合发展水平与分布状况。然后利用该综合指标,对各个城镇进行了空间统计分析,通过计算全局空间自相关指标,分析认为山东省各城镇综合发展水平总体上未呈现空间相关关系;通过计算局部空间自相关指标,分析认为山东省68.5%的城镇分布存在非相似空间集聚特征。     

FRAMEWORKS FOR GENERALIZATION CONSTRAINTS AND OPERATIONS BASED ON OBJECT-ORIENTED DATA STRUCTURE IN DATABASE GENERALIZATION

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A marine remote sensing spatial database engine for web publishing

To meet the requirements of efficient management and web publishing for marine remote sensing data, a spatial database engine, named MRSSDE, is designed independently. The logical model, physical model, and optimization method of MRSSDE are discussed in detail. Compared to the ArcSDE, which is the leading product of Spatial Database Engine, the MRSSDE proved to be more effective.     

一种面向网络发布的海洋数据库引擎

To meet the requirements of efficient management and web publishing for marine remote sensing data, a spatial database engine, named MRSSDE, is designed independently. The logical model, physical model, and optimization method of MRSSDE are discussed in detail. Compared to the ArcSDE, which is the leading product of Spatial Database Engine, the MRSSDE proved to be more effective.     

GIS技术在矿产地数据库及管理信息系统中的应用

采用ArcGIS平台开发矿产地图形输入编辑模块,并实现基于SQL Server 2000数据库的网上发布。一方面实现矿产地空间图形信息和属性信息网上浏览、检索和统计功能,另一方面也实现了矿产地空间图形数据的输入输出、编辑和转换功能。     

An Improved Hilbert Curve for Parallel Spatial Data Partitioning

A novel Hilbert-curve is introduced for parallel spatial data partitioning, with consideration of the huge-amount property of spatial information and the variable-length characteristic of vector data i...     

地籍管理中时空数据模型研究

地籍信息系统是一种典型的时态地理信息系统,其技术关键就是在于用适当的时空数据模型来组织地籍数据库。本文简要介绍了几种主流的时空数据模型,重点从建模方法、时空数据组织和时空数据操作三个方面阐述了地籍管理领域时空数据模型的研究进展,探讨了存在的问题,提出了未来发展方向的建议。     

Internet GIS上矢量型空间数据传送的最优化策略

作为在Internet上处理大空量空间地理信息的基于客户端的Internet地理信息系统（client-side Internet GIS)，解决矢量型空间数据传送的低效率性是很重要的，该文为此提出一个新的有效方法，首先，将大型矢量地图根据适当的“分裂度”分割成若干部分，每一部分称作一个“炔”（Tile)，当用户在客户端请求地图的某一区域时，GIS服务器中传递和请求区域相关叠的“块”内的空间数据，并且将该数据存在用户的本地机上，以便使用。为此，该文提出一个“地图块分割”方法，地图块查询处理”算法以及“客户服务器间空间数据的效率化传送”策略，和既存传送方法比较，利用该方法构造的Internet GIS,系统的整体效率得到了提高。     

HydrIS: An open source GIS decision support system for groundwater management (Morocco)

A regional groundwater management system has been elaborated, integrating Relational Database Management System (RDBMS) and various web services. It consists of web geospatial application so-called HydrIS (Hydrogeological Information System) based on Open Source components and technologies, leading to a feasible and low-cost solution. Therefore, HydrIS permits delivery of data from a number of heterogeneous sources to standards supported by the Open Geospatial Consortium (OGC). The protocols used for exchanging data are also derived from OGC standards, i.e., WMS (Web Mapping Service), WFS (Web Feature Service), and WCS (Web Coverage Service). Finally, a geoportal was developed, which consists of client-applications that communicate with different Web Services (WMS, WCS, and WFS) through http-requests.     

HydrIS:一个用于地下水管理的开放的GIS决策支持系统——以Morocco为例(英文)

A regional groundwater management system has been elaborated, integrating Relational Database Management System (RDBMS) and various web services. It consists of web geospatial application so-called HydrIS ( Hydrogeological Information System) based on Open Source components and technologies, leading to a feasible and low-cost solution. Therefore, HydrIS permits delivery of data from a number of heterogeneous sources to standards supported by the Open Geospatial Consortium (OGC). The protocols used for exchanging data are also derived from OGC standards, i.e., WMS (Web Mapping Service), WFS (Web Feature Service), and WCS (Web Coverage Service). Finally, a geoportal was developed, which consists of client-applications that communicate with different Web Services (WMS, WCS, and WFS) through http-requests. A prototype for web-based GIS application was designed using the deegree Framework to provide systematic interfaces and functions. This system was developed to demonstrate the value of making hydrogeological data more widely accessible through client/server architecture. This experience and knowledge already gained in this project will be a source for technology transfer and policy decisions. Otherwise, this will enable user groups to improve the management of their groundwater resources and contribute to enhanced decision support capabilities.      

An accurate selectivity estimation method for window queries and an implementation thereof

Spatial selectivity estimation is crucial to choose the cheapest execution plan for a given query in a query optimizer. This article proposes an accurate spatial selectivity estimation method based on the cumulative density (CD) histograms, which can deal with any arbitrary spatial query window. In this method, the selectivity can be estimated in original logic of the CD histogram, after the four corner values of a query window have been accurately interpolated on the continuous surface of the elevation histogram. For the interpolation of any corner points, we first identify the cells that can affect the value of point (x, y) in the CD histogram. These cells can be categorized into two classes: ones within the range from (0, 0) to (x, y) and the other overlapping the range from (0, 0) to (x, y). The values of the former class can be used directly, whereas we revise the values of any cells falling in the latter class by the number of vertices in the corresponding cell and the area ratio covered by the range from (0, 0) to (x, y). This revision makes the estimation method more accurate. The CD histograms and estimation method have been implemented in INGRES. Experiment results show that the method can accurately estimate the selectivity of arbitrary query windows and can help the optimizer choose a cheaper query plan.     

GIS中空间数据最小凸包串行算法的改进

针对传统最小凸包算法无法快速处理数据量较大的空间数据这一不足,该文通过分析最小凸包的性质,对传统的最小凸包串行算法进行改进,以提高最小凸包的构建效率。首先将空间点群分为绝对凸包顶点、可能凸包顶点、绝非凸包顶点三类,然后将大量的绝非凸包顶点剔除,仅仅判断可能凸包顶点中哪些点是构成最小凸包的顶点,最终和绝对凸包顶点构成所需要的最小凸包。通过对比分析,该文改进的方法原理正确,在遍历点的数量上较传统串行算法具有明显的优势,算法执行效率较高。