基于GIS技术的我国大气可降水量分布研究

利用分布于全国范围内的125个气象探空测站点(每日8:00和20:00)的探空数据,应用数据库编程与GIS技术,对大气可降水量在全国的分布情况进行了分析,得到了2002年全年以及春夏秋冬4个季节(2001年12月和2002年1,2月作为冬季)的平均大气可降水量在全国的分布状况。对数据进行分析可知:在空间上,我国的大气可降水量总体呈东南多,西北及青藏高原地区少的分布状况。同时,由于地形组合状况的特殊性,导致四川盆地、天山北麓等地区的大气可降水量略高于其周围地区;在时间上,夏季的大气可降水量值较高,可达到62mm左右,冬季较少,而春秋季除局部地区外大气可降水量基本持平。     

增城国土资源数据整合研究

信息孤岛是信息化建设的必经过程,信息共享是智慧城市建设所要解决的重点问题。作为智慧城市的重要组成部分,智慧国土的建设必然需要对国土资源数据进行整合。本文基于现有研究成果,结合增城市国土资源数据的实际情况,提出基于数据仓库的国土资源数据整合方案,并对增城市1∶2 000的空间基础数据进行了有效整合。     

区域规划空间信息系统建设与应用研究——以江苏省城乡规划信息系统为例

区域性城乡规划信息系统建设开展较晚,与城市级规划信息系统不同,其应用需求、数据构成、技术架构具有其独特性。结合新一轮江苏省城镇体系规划修编工作,开展全省城乡规划信息数据建库和应用平台的开发工作,系统根据区域规划的编制和研究应用需求,制定了面向未来区域规划工作需求的数据标准,集成了全省多源、多尺度、多时态的空间数据,实现了跨专业、跨平台空间信息的整合与共享。为江苏省城镇体系规划以及其他相关编制提供数据分析、规划决策支撑等服务,并预留未来与其他各类地理信息系统的应用接口。     

集群并发环境下大规模矢量数据负载均衡算法

为了提高集群环境下网络地理信息系统(WebGIS)大规模矢量数据的并发访问性能,提出了集群并发环境下大规模矢量数据内容网格化负载均衡算法,研究了大规模矢量数据内容网格化方法,集群并发访问时内容网格的自动识别、分析、聚合、反馈算法,实现了面向任务的负载均衡。实验表明,本算法能在大规模、高强度的矢量数据提取和显示中均衡地分发请求,使集群服务器充分发挥其优势从而获得最小的请求响应时间。     

Measurement of similarity for spatial directions between areal objects

Similarity for spatial directions plays an important role in GIS. In this paper, the conventional approaches are analyzed. Based on raster data areal objects, the authors propose two new methods for measuring similarity among spatial directions. One is to measure the similarity among spatial directions based on the features of raster data and the changes of distances between spatial objects, the other is to measure the similarity among spatial directions according to the variation of each raster cell centroid angle. The two methods overcome the complexity of measuring similarity among spatial directions with direction matrix model and solve the limitation of small changes in direction. The two methods are simple and have broader applicability.     

Multi-resolution seamless image database

This paper presents the basic concepts and principles, data structure and high efficient spatial index for multi-resolution image database. The database is characterized by arrangement of multi-resource image data and seamless mosaic, distribution-based storage and management, integration with other spatial database software such as GeoStar and GeoGrid developed by Wuhan Technical University of Surveying and Mapping.     

Development of a data mining method for land control

Land resources are facing crises of being misused, especially for an intersection area between town and country, and land control has to be enforced. This paper presents a development of data mining method for land control. A vector-match method for the prerequisite of data mining i. e., data cleaning is proposed, which deals with both character and numeric data via vectorizing character-string and matching number. A minimal decision algorithm of rough set is used to discover the knowledge hidden in the data warehouse. In order to monitor land use dynamically and accurately, it is suggested to set up a real-time land control system based on GPS, digital photogrammetry and online data mining. Finally, the means is applied in the intersection area between town and country of Wuhan city, and a set of knowledge about land control is discovered.     

Towards an integral strategy for modelling uncertain geospatial data

This paper endeavours to put the discussion on errors and uncertainties in geographical information systems (GISs) in a more systematic way by examining the strength and weakness of discrete objects and continous fields, the two distinct schools of spatial data modelling. In doing so, it argues that neither discrete objects nor continous fields alone provide objective and complete representations of highly complex geographical phenomena, though there are good reasons for asserting that continuous fields are better suited to modelling spatial dependence, heterogeneity and fuzzines significant in geographical reality than discrete objects. Thus, there seems to be merit in adopting an integrated model incorporating analytical capabilities of fields and generalization functions of objects, for which extended TIN (triangulated irregular network) models along with their duals (Voronoi diagrams) provide a pragmatical solution.     

Integrated data processing method for GPS and INS field test over Rocky Mountain

The method of integrated data processing for GPS and INS(inertial navigation system) field test over the Rocky Mountains using the adaptive Kalman filtering technique is presented. On the basis of the known GPS outputs and the offset of GPS and INS, state equations and observations are designed to perform the calculation and improve the navigation accuracy. An example shows that with the method the reliable navigation parameters have been obtained.     

China Digital Ocean Prototype System

Abstract

Digital Ocean is a new research domain of Digital Earth. Because of the spatio-temporal, three-dimensional (3D) and intrinsically dynamic nature of ocean data, it is more difficult to make a breakthrough in this domain. The construction of the China Digital Ocean Prototype System (CDOPS) pushes Digital Ocean a step forward from its operation as a mere concept to its achievement as a realistic system. In this paper, the technical framework of the CDOPS is discussed, including its data, function, and application layers. Then, two key technologies are studied in detail that will enable the construction of the 3D ocean environment and the visualization of the ocean model output data. Practical demonstrations show that the CDOPS provides a technical reference for the development of Digital Ocean. This paper is based on an ongoing research project of the development of CDOPS that aims at the facilitation, integration, sharing, accessing, visualization, and use of the ocean data and model computing data from the Digital Earth perspective.