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The integration of heterogeneous geospatial data offers possibilities to manually and automatically derive new information, which are not available when using only a single data source. This paper presents a three-level schema integration architecture which consists of local schemas, mapped schemas, and a global schema, for global heterogeneous geospatial systems. we describe a machine-learning based approach for GIS schema matching. Our approach extends existing machine-learning approaches for (traditional) data mapping but departs from them due to the nature of geographic data. Our solution reduces the complex mappings by identifying different values of a determining property.

Historically, cellular automata (CA) is a discrete dynamical mathematical structure defined on spatial grid. Research on cellular automata system (CAS) has focused on rule sets and initial condition and has not discussed its adjacency. Thus, the main focus of our study is the effect of adjacency on CA behavior. This paper is to compare rectangular grids with hexagonal grids on their characteristics, strengths and weaknesses. They have great influence on modeling effects and other applications including the role of nearest neighborhood in experimental design. Our researches present that rectangular and hexagonal grids have different characteristics. They are adapted to distinct aspects, and the regular rectangular or square grid is used more often than the hexagonal grid. But their relative merits have not been widely discussed. The rectangular grid is generally preferred because of its symmetry, especially in orthogonal co-ordinate system and the frequent use of raster from Geographic Information System (GIS). However, in terms of complex terrain, uncertain and multidirectional region, we have preferred hexagonal grids and methods to facilitate and simplify the problem. Hexagonal grids can overcome directional warp and have some unique characteristics. For example, hexagonal grids have a simpler and more symmetric nearest neighborhood, which avoids the ambiguities of the rectangular grids. Movement paths or connectivity, the most compact arrangement of pixels, make hexagonal appear great dominance in the process of modeling and analysis. The selection of an appropriate grid should be based on the requirements and objectives of the application. We use rectangular and hexagonal grids respectively for developing city model. At the same time we make use of remote sensing images and acquire 2002 and 2005 land state of Wuhan. On the base of city land state in 2002, we make use of CA to simulate reasonable form of city in 2005. Hereby, these results provide a proof of concept for hexagonal which has great dominance.

Keyhole Markup Language (KML) is an XML-based spatial data description language of modeling and storing geographic features such as points, lines, images, polygons, and models for display in earth browsers. It's very convenient to use KML for spatial data description, however, KML lacks of description of terrain information that has important value in geology, hydrology, nature disaster monitoring and many other fields. In consideration of such shortcomings, we expand some functions based on the KML and present Distributed Spatial Data Markup Language (DSDML). DSDML can describe DEM and raster data of large size, and support customed terrain information application. This paper mainly researches on how to describe terrain data using DSDML and implement visualization, including designing a data organization model using quad-tree model and pyramid model, utilizing external linked DEM dataset for terrain description of large volume and DEM tile for terrain description of small volume, realizing a DSDML data parser based on SAX model and building a terrain buffer pool for terrain visualization to obtain a high performance mechanism. We make experiments on three-dimensional visualization platform with different data size, and the results demonstrate that DSDML can be efficient and effective for terrain description and visualization.

This paper firstly introduces the spatial data grid and the CDN (Content Delivery Network) technology. And then it depicts the significance of integrating grid with CDN. On this basis, this paper proposes a method of constructing the spatial data grid system by using CDN to support the massive spatial data online service. Finally, the simulation results by OPNET show that the programme do can improve the system performance, and reduce response time in a greater extent.

A huge amount of geospatial and temporal data have been collected through various networks of environment monitoring stations. For instance, daily precipitation and temperature are observed at hundreds of meteorological stations in Northeastern China. However, these massive raw data from the stations are not fully utilized for meeting the requirements of human decision-making. In nature, the discovery of geographical data mining is the computation of multivariate spatio-temporal correlations through the stages of data mining. In this paper, a procedure of mining association rules in regional climate-changing databases is introduced. The methods of Kriging interpolation, fuzzy c-means clustering, and Apriori-based logical rules extraction are employed subsequently. Formally, we define geographical spatio-temporal transactions and fuzzy association rules. Innovatively, we make fuzzy data conceptualization by means of fuzzy c-means clustering, and transform fuzzy data items with membership grades into Boolean data items with weights by means of e-cut sets. When the algorithm Apriori is executed on Boolean transactions with weights, fuzzy association rules are derived. Fuzzy associ ation rules are more nature than crisp association rules for human cognition about the reality. Keywords: Temperature, precipitation, fuzzy associa tion rules, spatio-temporal data mining

Along with the development of earth observation technology, large amounts of geospatial information are accessible. There are also a lot of geospatial data and services which ar e shared on the Internet. Howe ver they vary in formats and are stored at various organizations leading to problems of data discovery, data interoperability and usability. The Open Geospatial Consortium (OGC) has developed standard service called catalogue in order to overcome this problem. The goal of a geospatial catalogue is to support a wide range of users in discovering relevant geographic data and services from heterogeneous and distributed repositories. But in most of geospatial catalogue services, the search functionality is limited to the direct match of keywords from metadata, the OGC catalogues may not return useful results as the used keywords often do not match with the meta-information stored in the catalogues. In this paper, we propose a geospatial semantic catalogue services that aims at overcoming this limitation. Keywords: catalogue service, semantic, ontology, inte roperability, geospatial data and service

Spatial information dissemination is a necessary step to make use of spatial information for which is a bridge between the acquirement and the application of spatial information. However, conventional methods of spatial information dissemination cannot cater to users in that not only users' personalized requirements cannot be satisfied, but initiative dissemination service cannot be provided. In this paper, the idea of intelligent spatial information dissemination (ISD) is proposed. Combining the ideas of personalized information retrieval, information filtering and recommender systems, the ISD system employs user profiles and query conditions to provide two implement ways of spatial information disseminations, namely "pull" and "push". Then, the three layers architecture of intelligent spatial information dissemination system based on user profile model is given, and the procedure of data in the ISD system is introduced. Also, the user profile is presented including user profile model and user profile management. Finally, the prototype system of intelligent spatial information dissemination is presented.

Conventional spatial information delivery is system-oriented, and users have to adapt to the system and complete the delivery of spatial information. Two disadvantages exist in the delivery service mode: (1) users' personalized requirements cannot be satisfied; (2) Initiative delivery service cannot be provided for users. In this paper, we firstly classify conventional user profile models into four categories. After analyzing the limitations of these user profile models, we conclude that conventional user profile models are not suitable for the application of spatial information intelligent delivery. Then, aiming to the objectives of spatial information intelligent delivery, we propose a user profile model of spatial information, and give the building method of the model. Also, we put forward a similarity measure method between spatial information and user profile. In order to verify the availability of the user profile model, we present an example of spatial information intelligent delivery. The experimental results show that the proposed user profile model can reflect user profile quite well.

In the paper brings forward that complexity degree of land use structure can be used as one of quantitative indices to define the land use/land cover (LU/LC) status expression precision scale. Then by simulating population density spatial differences in Wuhan district, according to the value of complexity degree of land use structure, divides the experiment area into a kind of non-uniform and multi-grid structure. Consulting one grid cells' status high or low in the multi-hierarchy data structure, the LU/LC status expression precision scale rough or fine can be defined in a degree. Furthermore, the outcome of simulating population density shows that the multi-grids land data structure can integrate land use data with other social and economic statistics conveniently and neatly to complete some simple land data mining tasks such as the data computation or analysis effectively, then can reflect the LU/LC status of some region.

Nowadays, huge volumes of geospatial data and services are available and accessible to people all over the world. However, they are searched mostly based on keyword, which is inherently restricted by the ambiguities of natural language, which can lead to low precision and recall. In this paper, semantic share of geospatial data and services are studied based on ebXML registry. But ebXML registry specification doesn't take into account the registration of the semantic information. So we define how OWL DL constructs are mapped to ebXML registry information model (ebRIM) constructs without causing any changes in the core ebXML registry specification. After that, predefined stored procedures are provided in the ebXML registry for semantic search, which provide necessary means to exploit the enhanced semantics stored in the Registry. Then, geospatial ontologies in change detection application of remote sensing based on Global Change Master Directory, ISO19119 and ISO19115 are established. Finally, a prototype system is developed based on an open source-ebxmlrr to demonstrate the proposed model and approach.

The route computation module is one of the most important functional blocks in a dynamic route guidance system. Although various algorithms exist for finding the shortest path, they are faced with the networks in the local server not distributed environment. We present an efficient distributed hierarchical routing algorithm that can find a near-optimal route and evaluate it on a large city road network which is composed of a lot of small networks which are placed on different servers. Solutions provided by this algorithm are compared with the stand-alone traditional hierarchical routing solutions to analyze the same and different points. We propose two novel yet simple heuristic to substantially improve the performance of this hierarchical routing algorithm with acceptable loss of accuracy. The improved distributed hierarchical routing algorithm has been found to be faster than a local A* algorithm.

Spatial data sharing among multiple GIS (Geographic Information System) platforms is a fundamental requirement of many GIS applications, yet conventional methods of spatial data interoperability don't adequately consider practical application circumstance, which now becomes a primary barrier to more efficient spatial data sharing among multiple GIS platforms. In this paper, after analyzing the disadvantages of conventional methods and the causation of the disadvantages, and analyzing the principle of spatial data access of ArcGIS, MapInfo and GeoStar based on Oracle Spatial storage, the authors propose a new spatial data interoperability method called Different meta information and Same spatial data Method. This method is based on Oracle Spatial, through which spatial data interoperability for multi-platform of GIS is available. The results of experiments demonstrate that this method is a new simple practical approach adapted for current application circumstance, and it provides us a new idea for spatial data interoperability.

The Combination of Geographic Information Services (GIServices) is studied in this paper. First, the way of GIServices combination is analyzed. Based on GIServices combination ways depicted by Service-Oriented Architecture (SOA), OpenGIS (OGC) Web Services Architecture and International Organization for Standardization (ISO) 19119, GIServices combinations are classified into Discrete Service Combination, Chaining Service Combination and Hybrid Service Combination in this paper. Then, the model of GIServices combination is focused. A high-level GIServices combination model based on Petri Net is proposed to improve those proposed by former researchers. The proposed high-level model can represent services combination relationship more clearly and can help to control services combination behavior in an easier way. Since searching GIService that can accomplish certain GIS task is a key step of implementing GIServices combination, GIServices taxonomy is then studied. A multi-level task-oriented GIServices taxonomy is proposed in this paper. Correspondence between GIS tasks and GIServices can be established more easily with the proposed multi-level task-oriented GIServices taxonomy. Finally, a case study is made to support the proposed theories.

A portal is a powerful Web site that gives users a single point of access to applications and information in a unified interface. A portal lets users view each application or web page in its own window, called a portlet, and a single browser window can contain multiple portlets. The portlet based on JSP168&WSRP is a new technology for interactive, user-facing web services that plug and play with portals. Thanks to the development of Portal&Web GIS, the GIS Poratl is focused on more and more by the researcheres. This paper studies the GIS Portal defined by ESRI and analyzes the development's status, compares with the commercial Portal and points out the great shortage of the ESRI GIS Portal: lack in Personal content and UI. Therefor this paper goes into depth on the discussion of design and implementation scheme of real GIS Portal, and proposes the new idea of developing customized, plug and play GIS Portal Module based on JSP168 Portlet technology and WSRP standard. This way can resolve the difficult problem of the GIS Portal on lacking of content and customization function. According to this idea, this paper plans to use the JaveBeans provided by GeoSurf to develop visual portlet which have basic operating fuction of GIS. Finally deploys the GIS Portal uing the WebLogic Portal.

It is the GIS developing direction to integrate GIS with Internet. Internet GIS is not only used to publish distributed geographic information on line, but also to provide on line tools for distributed geographic information real-time analysis and processing. Internet GIS should make use of existing multi-sources and functions for geographic information analysis and processing. The distributed feature is inherent to geographic information, which needs distributed organization and processing approach. Internet GIS (Geographic Information System) is the integration of Internet and GIS, being used to implement publishing on line and distributed real-time analysis of geographic information. The problem of geographic information distributed management and processing should be solved by Internet GIS. This paper provides three approaches to the problem, especially the distributed component and Geo-Connector approach to Internet GIS. The distributed component method includes homogeneous, heterogeneous and conjoint methods, for the problem of distributed geographic information publishing and real - time analysis. With instance, the feasibility and practicability of distributed component method are interpreted in detail. The concept of Geo-connectors in GIS application server side for organization and management of distributed heterogeneous database is presented and a case of heterogeneous geo-data access and interoperability is studied

A systematic plan of building Web Geographic Information System (WebGIS) using ActiveX technology is proposed in this paper. In the proposed plan, ActiveX control technology is adopted in building client-side application, and two different schemas are introduced to implement communication between controls in usersi¯ browser and middle application server. One is based on Distribute Component Object Model (DCOM), the other is based on socket. In the former schema, middle service application is developed as a DCOM object that communicates with ActiveX control through Object Remote Procedure Call (ORPC) and accesses data in GIS Data Server through Open Database Connectivity (ODBC). In the latter, middle service application is developed using Java language. It communicates with ActiveX control through socket based on TCP/IP and accesses data in GIS Data Server through Java Database Connectivity (JDBC). The first one is usually developed using C/C++, and it is difficult to develop and deploy. The second one is relatively easy to develop, but its performance of data transfer relies on Web bandwidth. A sample application is developed using the latter schema. It is proved that the performance of the sample application is better than that of some other WebGIS applications in some degree.

The Virescence Separator of Beijing, the capital city of China, is a virescence zone between the central area and the edge group as well as the zone among different edge groups, within irregular shape and the total area of 240 square kilometers. The construction of the Virescence Separator is a big and difficult project, an effective information system for planning and development with satisfactory performance is therefore essential. In this paper, the applications of remote sensing and GIS (Geographical Information System) technologies in BJVSIS (planning and development Information System for Beijing Virescence Separator), including three dimensional (3D) visualization, integrated databases management and multi-media technologies, were presented. The initial pilot project of BJVSIS was finished successfully in 2001, and up to now this information system runs very well and plays a great role in the construction of the Virescence Separator. Just depended on the applications of so many high-tech like GIS, remote sensing, 3D visualization, and databases integration, BJVSIS can manage all kinds of relevant geographic data, such as vector graphics, DEM (Digital Elevation Model), image and multi-media attributes. And BJVSIS also provides many GIS functions, such as spatial query, 2D/3D display, spatial analysis, statistic calculation, form report and map output.

With the increasing maturity of distributed object technology, CORBA, .NET and EJB are universally used in traditional IT field. However, theories and practices of distributed spatial database need farther improvement in virtue of contradictions between large scale spatial data and limited network bandwidth or between transitory session and long transaction processing. Differences and trends among of CORBA, .NET and EJB are discussed in details, afterwards the concept, architecture and characteristic of distributed large-scale seamless spatial database system based on J2EE is provided, which contains GIS client application, web server, GIS application server and spatial data server. Moreover the design and implementation of components of GIS client application based on JavaBeans, the GIS engine based on servlet, the GIS Application server based on GIS enterprise JavaBeans(contains session bean and entity bean) are explained.Besides, the experiments of relation of spatial data and response time under different conditions are conducted, which proves that distributed spatial database system based on J2EE can be used to manage, distribute and share large scale spatial data on Internet. Lastly, a distributed large-scale seamless image database based on Internet is presented.