DEM(Digital Elevation Model) is the model of terrain and relief, and also a fundamental digital product of the nation. It has been widely used in many areas. The author firstly analyses two existing diverse episte-mological viewpoints of the ground, and then clarifies that the ground exterior is a certain exterior which consists of several curved surfaces based on complicated terrain frame lines, indicating that the viewpoint which regards the ground exterior or part of it as a stochastic surface does not tally with human life and production practice. Through the property analysis of system errors and accidental errors together with the analysis of DEM production, the author also indicates that using only accidental errors to estimate DEM errors ignores the process of interpolation and gives out an incorrect property of interpolation errors. At the same time the premise setting and some mistakes in the process of illation in DEM accidental error calculating are discussed in the paper. Finally the author points out that using accidental errors to estimate DEM errors has been in hot water and does great harm to the check method and standard of DEM errors, so as to reduce the quality of DEM products.

The fusion of images of remote sensing not only improves the resolution of image, but also preserves the multispectral features. A method, which is the combination of wavelet transformation and IHS transformation, is described in this paper. The fusion of multispectral bands and panchromatic band of ETM images is achieved by using this method. The result of the fusion indicates that the method of combination of wavelet transformation and IHS transformation is more advanced than the method of IHS transformation in the fusion of multispectral bands and panchromatic band of ETM images.

In a distributed spatial database system, spatial data is currently shared with a snapshot-based mechanism. This method is charcateristic of maintaining copies of remote spatial datasets in local databases, and thus inevitably results in great data srorage redundancy and difficulty in preserving data consistency. In this paper, however, a view-based sharing method is put forward to solve this problem. Firstly, a local view is created corresponding to a remote spatial table, then an 'instead-of trigger for modifying each row is set up on the view to enable it modifiable. So local access to remote spatial data in a distributed database environment can be implemented with the extended view-modifying functions and view-selecting functions directly from Database Management System (DBMS). A case based on an Oracle 9i database management system validates the feasibility of this view-based data sharing mechanism, with a satisfactory result.

Workflow management is a new research area and is known as "logistics" of information systems. It can arrange suitable people or software to perform right tasks at right time and automate business process. According to the requirement of Land Use Planning Geographic Information System (LPGIS), based on the referenced model which is called Workflow Management System (WfMS) and with the support of technology of ArcObjects and SQL-Server, this study overcomes a series of difficulties, brings out the general framework of the system and gives an example relating to the applications.

This paper, based on analysis of characteristic and application conditions of MapX, introduces structure and function of thematic map managing information system in Changchun and discusses the method of developing thematic map managing system by utilizing MapX control. It proposes method to realize thematic map management,double direction selection,database linkage and analyzes in detail some technical difficulties and methods resolving these problems in system building.

With the rapid development of the Web technology, GIS has entered a brand-new stage. Web technology brings geographic information so great impetus that it can be more open and popular to the public, industries and departments. WebGIS, which combines the Internet web technology with GIS technology, has become an important research direction of GIS. WebGIS is a good approach to get GIS data and geographic information service for us. But WebGIS also confronts some problems for the further development, such as absence of interaction and limitation of accessing heterogeneous database. So WebGIS needs some new technologies to solve these problems. XML is a new technology, which promotes the development of Web. GML specification is defined by OGC. Its purpose is to transport and store geographic information in XML format, which will play an important role in the development of WebGIS. This paper analyzes the problem that the WebGIS exists in spatial data sharing and in bandwidth of network at first. It then discusses the GML and SVG as well as the application of GML and SVG in WebGIS. On the basis of general architecture of WebGIS, the author presents a new architecture based on GML and SVG. The architecture is made up of three layers: database, application and client. This paper analyzes the architecture in detail and explains the characteristic of the architecture. And then it introduces some key technologies in detail such as parsing GML document, translating GML to SVG and so on. Finally, this paper provides the application example of this architecture and gives the picture of the WebGIS prototype system interface.

Land and resources information contains multiplicate data source and mass volume of data. Moreover, new data is being generated in daily management. All these have increased the practical difficulties in the management and services of land and resources information. In the current management of land and resources in China, it is urgent to exchange and update information periodically or real-timely between superior department and junior department in China, that is between relevant government departments at national, provincial, municipal or prefectural levels. In the above data, spatial data concerning land monitoring, mining and geologic surveying dominate in information management and services.Facing at the above status, this paper has introduced the general idea of information exchange of land and resources. That is to set up a unique data center at the national level; data is gathered from municipal level to provincial level, then from provincial to the data center (national level) gradually. In light of this idea, data is backuped incrementally in data center. Also, information can be exchanged real-timely under the uniform network system. According to the above general idea, this paper has also analyzed the exercisable pattern and practical techniques, in which GML-Geography Markup Language is emphasized.

This article uses the quantitative graph of oblique coordinate system as a way to express the quantitative information in the thematic map, which expands the expression ways of the thematic map. The author also introduces the application program' s design idea of the quantitative information visualization of thematic map by using oblique coordinate system graphs. By analyzing the structure and visualization variables of oblique coordinate system graphs, the author abstracts a basic rhombus. Based on the MapBasic macro language of the Mapln-fo software, the author designs a standard sub of the basic rhombus of oblique coordinate system graphs. The single coordinate system graphs, the double coordinate system graphs and the multi coordinate system graphs are all composed of the basic rhombus. The drawing models of the single, the double and the multi coordinate system graphs are developed by calling the standard sub of the basic rhombus. In the Mapbasic development environment, the application program uses the Mapbasic project file to connect each model. Based on this mode, the author developed an application procedure of the quantitative information visualization of thematic map by using oblique coordinate system graphs. The application procedure has the single coordinate system graphs, the double coordinate system graphs and the multi coordinate system graphs models. Also the application procedure has some special functions such as graphs sorted automatically or sorted by hand, adjusting the graph's location by the mouse. At the end of this paper the author drews a thematic map by using the data of Hebei province, which using the graphs of the three coordinate systems combined at center. In this way, the author validates the graph' s application effect in thematic mapping.

Geofracture, as one of the severe geological hazards appearing in Xi'an area, has become considerably serious. The factors influencing the result of the geofractures in Xi'an include structural movement, groundwater mining, geomorphology and stratigraphy. The MAPGIS, a geographic information system, has a unified analytic capability in geographic coordinates and spaces. In this article, the geographical information system, MAPGIS, is used for assessment of the intensities of geofracture activities. Based on the analysis of the influencing factors of geofratures, an analytical model for different levels has been created, each weight of influence factors is calculated and an assessment model under the support of GIS for geofracture activities confirmed. Then, according to the modules of MAPGIS maps and image processing, algebraic calculation of maps on some special topics for individual factor has produced superposed images with the influencing factors of geofractures and confirmed the value of division. Based on the results, the active intensities of geofractures in Xi'an area can be partitioned and predicted.

In this paper, the effect of atmospheric impact and the requirement for atmospheric correction is explained firstly. Then the universal problems about atmospheric correction are expatiated. Atmospheric correction includes two major steps. The first step of atmospheric correction is retrieval of the concentrations of atmospheric molecules and aerosol. The method about retrieval of water vapor and aerosol is discussed. The radiative transfer programs (softwares) such as MODTRAN, 6S,SBDART, are commonly used in the calculation of atmospheric correction functions, the methods for calculation of atmospheric correction functions is also reviewed. The second step of atmospheric correction is surface reflectance retrieval from model. Several models to describe the bounces between atmosphere and surface are summarized. As for all the atmospheric parameters, the retrieval of surface reflectance is relatively straightforward when the surface is assumed to be lambertian. The retrieval of surface reflectance from surface which is heterogeneous and non-lambertian is also discussed. The method for dealing with adjacency effect, the creation of look-up table, and the precision analysis for the atmospheric correction result are summarized in the rest of the paper, too.

This paper analyses the structure of ArcIMS 9 software at first, the importance of ArcXML is found, but the ArcIMS software has shortcoming in building the ArcXML request information and parsing the ArcXML response information. In order to make up the above disadvantage, a method is described which is built in the Microsoft .Net developing environment. Then the MVC design mode is adopted by this method to the design of the WebGIS control, every component ' s function of the MVC is described in detail. The control tie' s function is to build ArcXML request information and parse the response information, the main classes' relationship diagram of the control tie is showed and the every component' s function is explained. Finally, it summarizes the advantage of this method which integrates the advantages of the MVC design module, .Net developing environment and ArcIMS function. By using the above control to build the WebGIS system will save time for program developers.

Although Mountain Altitudinal Belt Spectra Information System (1.0) has succeeded in digital integration of mountain altitudinal belt spectra, it has still deficiencies to be improved and perfected, including occasionally label illegibility, unchangeable color arrangement of altitudinal belts, dissatisfactory display of a great number of mountain altitudinal belt spectra. This paper explores the technical improvement and perfection of Mountain Altitudinal Belts Information System 1.0 (MABIS 1.0), mainly in spatial visualization of mountain altitudinal belts spectra, including the brief design process, spatial data labels, page rolling, color customization, operable data axes, etc.The result shows that perfection of spatial visualization in MABIS can not only efficiently manage the mountain altitudinal belts spectra, but can also facilitate visualizing the selected mountain altitudinal belts spectra data expediently and directly, discovering the spatial distribution pattern of mountain altitudinal belts of interest. This also lays a solid foundation for developing the World Mountain Altitudinal Belts Information System (MABIS).

Recently,ASTER satellite data has been frequently used as a new remote sensing data source. This paper deals with the research and process of image mosaiking, which takes Fukang as a study area and makes use of remote sensing image disposal software ENVI. The research result indicates that ASTER satellite data embodies a good many advantages. Meanwhile, the paper discusses the problems of image mosaiking and development trend in the future.

The technology based on OLE development can bring the strong function of the mature geographic information system software and the object oriented development language together, but there still exist some problems in call-back mechanism and the massive spatial data managements. This article, taking the development of geographic information system of Taining as an example, introduces emphatically the call-back mechanism based on OLE technology, MapInfo object, the class used to achieve the communication between MapInfo and application, form class and the methods of using them. With this as the basis, the author put forward the method of carrying on the advantage of large distributed database MYSQL and of managing the map and properties data separately to manage massive spatial data, in order to resolve the system movement speed slowness and perfect the method of visiting database.

The raise of "Digital Earth" strategy has aroused concern of personages of various circles, and contributed suggestions from their respective disciplinary angles. But the implementation of "Digital Earth" strategy must take area or special topic as the point of penetration. This paper, proceeds from the background of relatively severe desertification in China's arid and semiarid areas and the western development aiming at eco-environ-ment construction, in combination with physical and human characteristics of the study area, designed the land desertification information system in arid and semiarid areas in terms of the whole structure, function, model of arid and semiarid area desertification GIS. The system consists of three subsystems, namely, the database administration subsystem, the subsystem for inquiry of land desertification information, the subsystem for managing the model database. Meanwhile the selection of the representative demonstration area has been put into practice. The result indicated that, although the system needs to open up and improve further, the correlativity of the system's data term has satisfied the function and model demand of the present special topic's GIS system. This information system can provide quick, dynamic information and technique support for prediction and evaluation of the eco-environmental deterioration and land desertification, as well as for timely adopting prvention measures and countermeasures by decision-making department.

The paper paid much attention to Virtual Geographical Environments of ideal equilibrium profile lines of rivers. Surface runoff is one of the important factors figuring the earth's surface. The reconstructing action on the earth's surface by fluvial process, which includes erosion, mass transportation and accumulation, results in erosion and accumulation of landforms, and these two types of landforms have close relations with each other. Based on the mechanism of the formation of the equilibrium profile line of rivers presented by the geomorpholo gists, the paper deduced the theoretic formula of the equilibrium profile line. Because there are three landform stages in China from west to east, the paper calculated three equilibrium profile lines of the Huanghe River: L1 was the total equilibrium profile line of the Huanghe River, L2 and L3 were local equilibrium profile lines which took Togtoh or Songduo as local datum planes. The equilibrium profile lines of the Huanghe River have theoretic significance on the researches of the development of rivers and their capabilities of erosion and transportation.

Aiming at concrete conditions of using SST (sea surface temperature) to carry out the prediction and analysis of fishing ground in the field of ocean fishery, according to the designing requirement of the applied geographical information system, we have finished demand analysis, general design and function design, consequently taking ArcGIS software as the developing platform to develop the prototype system in view of the above. The system adopts of model of a three-tier structure, applies RDBMS to manage spatial data, and realizes the seamless management of the integration of spatial data with attribute data seamlessly. And it uses sophisticated COM technology and advanced WebService technology to integrate and distribute the system, which guarantee systematic reliability, regularity and extensibility, thus providing decision support for department of ocean fishery.

In order to integrate existing land information and realize land information exchange and sharing,the key task at present is to build land & resources clearinghouse. Taking land register as an example, this paper explored the domain knowledge expression of register and requestor of web services based on the ontology technology, realized the retrieval, matching and learning of web services by combining OWL-S Ontology description language with WSDL and resolved the UDDI semantic description and discovery for land information. It also put forward a land information web services frame based on ontology and an elementary process.

The Topographic Wetness Index (TWI) is frequently used to simulate the soil moisture conditions in a watershed quantitatively. The index that extracted from DEM is an important factor with explicit physical significance in the rainfall-runoff process models. Some previous studies discovered that the TWI would change with the resolution of DEM from which it was derived and this change, and terrain heterogeneity of DEM grids were employed to explain the scale dependency. In this paper, we explored the resolution effects of TWI and the influence of terrain heterogeneity of DEM grids. The research area is located in Xiyuanxi watershed, Xiamen City of Fujian Province, which includes different terrain types such as hill, platform, plain, etc. A fine-resolution DEM with 2.5m grid size was used to investigate the scale dependency of TWI values when converting DEM with resolution of 20m. Four terrain and heterogeneity attributes were employed as the quantitative indices of terrain heterogeneity of DEM grids, i.e. standard deviation of elevation, relief, landscape fragmentation index and landscape diversity index. The correlation and regression analysis was performed to identify sensitive and correlative responses between each terrain heterogeneity index and TWI variance as resolution was changed. The results indicated significant negative correlations between the terrain heterogeneity indices and the TWI variance (the Pearson correlation coefficients were -0.707, -0.712, -0.779 and -0.841 respectively, all based on a high confidence level of 0.01). By extrapolating the fitted curve for the terrain heterogeneity indices and TWI variance, the logarithmic curves fit the optimal equations well (the coefficient of determination are all greater than 0.9, F>F_0.01). So, these indices can be used to evaluate the impact of the terrain heterogeneity on the TWI. Meanwhile, the regression models can improve the accuracy of the TWI derived from a coarse resolution DEM. The effect discussed in this study is helpful in providing a more accurate data for the TWI applications.

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As a consequence of industrialization and urbanization, a large amount of pollutants are spread in the agricultural soils: solid materials and aerosols which contain organic matters as well as inorganic harmful materials, toxic elements and heavy metals contamination of soils has become increasingly serious, the safety of the farm produce is being paid more and more attention by people. This paper is about combining Visual Basic 6.0 with a set of components of map software developed by ESRI-MapObjects 2.0 to program farm produce safety management system in Zhejiang province. The provincial 1:250000 spatial database and regional 1:50000 remote sensing imagery were established and combined with the attribute database of crop sampling sites and the standard database of farm produce safety to realize some functions and operations for sampling sites distribution map of provincial scale and some important counties scale such as zooming,roaming,labeling,consultation and statistics etc., the system can not only display specially the attributes of soil and crop samples and their operation results, it can also update the correlative information. This study provides a rational and efficient platform for the information management of farm produce safety in Zhejiang province.

With the development of Information technology, Geographical Information System and database, the applied Information System based on GIS and tourism has been accepted by people gradually and has obtained a unprecedented developing space. This kind of system uses GIS software as the platform. They can exactly store varied spatial data, image data and multimedia information. With the capability of spatial operation, special map management, the system can offer information query and display function. The abundant query results can be displayed on the screen instantly and directly. The GIS technology system, theory of application of GIS software and developing mode of component GIS are discussed in this paper based on the plenty internal and external references. To meet the practical needs of tourism, we have designed and developed the Yuan Ming Yuan Tourism Information System(TGIS). MapGIS-a GIS platform software - is used to digitize map on screen to vector data, and then it is turned into Arcview shapefiles. Image data and attribute data are integrated in Arcview and stored in graphic database and attribute database with the shapefiles format managed by Arcview. In the system integration, VisualBasic is used as a programming tool with the embedding GIS component MapObjects. And with the VB.ADO technology, we have integrated the Access data. Many functions such as spatial/attribute information query, dynamic display of tour routes, graphics output, etc. are realized in The Yuan Ming Yuan Tourism Information System.

As the largest freshwater lake in China, the environment characteristic of Poyang Lake is very special, hence it is very significant to carry out research by means of integrating multi-source spatial data in order to improve our scientific understanding about this area. This article introduced the step of constructing the Poyang Lake spatial information system and virtual environment viewing system. The system consists of a series of theme spatial database and basic GIS database. With the help of the VR-Map software, it is possible to realize the virtual 3D visualization of the terrain. And with the help of the ArcGIS software, it is possible to generate all kinds of theme maps, such as DOM (digital orthodox map), land use maps, population distribution maps and so on. Maps of good quality are very important to the research work. These maps can be updated immediately when the basic data are updated.

With the deepening of informanization development, the range of computer and internet / intranet application and the scale of the application systems are expending. A common problem that lies ahead of us is how to integrate with and share the information resources that have been built. Taking the project of the e-government information sharing platform of Fujian Provincial Digital Forestry as an example, based on protecting the investment in information, the overall solution scheme and realization methods of the information exchange and sharing are studied by means of MS.NET/ XML & Web Services / MS BizTalk Server 2004 core technologies for the sharing information requirement of Fujian Provincial Digital Forestry application systems in forestry of the data distributed and heterogeneous environment.

The quality of data is very important in GIS. Due to various reasons in the process of GIS data production, the data' s quality is usually full of uncertainty. It is difficult to give an impersonal evaluation on these data, and the normal use of these data is disturbed. In this paper, the concept of fuzzy mathematics is introduced to evaluate the quality of GIS data. The evaluation model for data quality of GIS is built through fuzzy mathematics theory. In the process of the model building, the evaluating factors, evaluating set, the conformation of factors' weightiness and membership function of the evaluation set are introduced. A practical example is given to explain how the method was used to evaluate the vectoral production. This method can solve the impersonal evaluation of the quality of GIS data effectively, and lead the evaluation of the products of vector data become easier and intuitively when using this method. The quality of data is guaranteed.

Loess Plateau has long been receiving intense attention from geomorphologists and cartographers because of its special landscape. The traditional expression methods, such as written text, relief maps and images do not seem instinctive and effective to show the true landscape features. Geo-Info-TUPU, an innovation in the theory, methodology, product and application of Geo-System Science and Geo-information Science, discloses and indicates the internal laws hidden in geographical objects and phenomena and generally is denoted with maps, images, graphics, diagrams, etc. 3D visualization technology is a very important method to reconstruct three dimension sense and help to reveal the true visage. Thus, Geo-Info-TUPU plus 3D visualization technology will be a very appropriate method to effectively express the landscape features of Loess Plateau.Landscapes TUPU of Loess Plateau reveals the laws of landscape features with image, 2D and 3D graphics. The research results of the former geomorphologists and cartographers are carefully studied by using graph thinking, extraction, generalization and data mining methods and the laws of landscapes features are extracted. Horizontal and vertical feature indexes, including detailed qualitative and quantitative ones, of positive and negative landscapes of Loess Plateau, are established, and therefore give important references to 3D modeling, Accurate description for all kinds of landscape models will be very helpful to cognize and research the true features and will be meaningful for the virtual reform and forecast of Geo-objects. This experiment not only is an example of applying Geo-Info-TUPU but can also help to cognize, to express and even to protect the landscape of Loess Plateau.

By using Geo-information technology synthetically, this paper makes an in-depth analysis of the changing characteristic and driving force of land use in Fuzhou city. The main research contents include: to take TM data as information source to obtain two periods of land use state and this period of land use change information; to offer accurate space positioning information and fast localization of field investigation of the changing areas quickly with GPS; to use GIS to deal with data of many kinds of sources synthetically, including the integrated management, spatial statistics and synthetical analysis, use of the other data of the statistics and GIS management to carry on canonical correlation analysis, and to use variable of canonical correlation to explain the question of driving force of land use changes in Fuzhou city. Through spatial statistical analysis and canonical correlation analysis, we got to know that the area of land use change in Fuzhou city is distributed in all parts of the whole city, especially the eastern coastal area and around the basin of Fuzhou city .The variation tendency is that the paddy field and nonirrigated farmland show a decreasing tendency, but the forest land, water areas, construction land, garden plot and meadow show an increasing tendency. The change of land use is influenced both by the natural and socio-economic factors synthetically, the main influencing factors are the slope, average wind speed, per capita cultivated land, per capita grain sown area, rural workforce's density, income of township enterprise, grain per mu yield, net income of peasants, per capita agricultural gross output value, gross domestic product, per capita total volume of retail sales of social consumer goods etc.

With statistical analysis and visualization, this research analyzes the characteristics of concerned domestic cities and airlines and competitive situation for the nine Chinese airline companies, based on latest Chinese civil aviation flight information for 60 delicately sampled Chinese cities. It is shown that the airlines of the three big aviation companies and Hainan airlines have formed multi-hub networks with high connectivity, while the other five companies only have single-hub or double-hub radial networks. The three big companies and Hainan airlines have apparent advantages of operational monopoly, and also intensive competition between them. Contrarily the other airline companies stand in apparent inferior competitive positions on the crucial airlines constituting Chinese civil aviation transport networks. The research is expected beneficial to airline and flight adjustment, code sharing and civil aviation policy enaction.

In this paper, a new approach based on combining two radically different texture features is proposed for similarity retrieval of multi-source remote sensing database. One takes a statistical approach in the form of gray level co-occurrence matrix (GLCM), the other takes a signal processing approach with tree-structured wavelet transform or wavelet packets. Particularly, we also combine texture feature with spatial relation in the statistical method. The similarity retrieval contains six consecutive stages: preprocessing the images in the multisource remote sensing database, feature extraction, feature sequence normalization, weights for feature elements, similarity measure, and experimental evaluation. Through comparison with other methods: such as the gray level co-occurrence matrix, the tree-structured wavelet transform or wavelet packets, in combination GLCM with special relation, the proposed method shows good tradeoff between retrieval effectiveness and efficiency. The experimental results indicated that the combined texture retrieval way has powerful practical merits.

Smart client is the client application easy to deploy and manage. Taking the advantages both in B/S and C/S, it has a bright future in many different fields. Through analyzing the feasibility in data-sharing system and taking lake and watershed data-sharing system as an example, this paper introduces a method of how to design and build data-sharing system based on smart client. First, the paper divides the data-sharing system into six different parts, including user identification, data produce inquiry and order, data encryption and download management, data decryption and visualization, connection and updater management. It discusses the details of the technology which are applied in each part. Smart Client Application blocks are the essential components to build a smart client application. Lake and watershed data are the basic elements of the geo-data database. Lake and watershed data center has collected mass data for the scientific research of related fields. Building a data-sharing system is very important for scientists to access the essential data. Considering much of the data concerning the national security, this paper brings network security into data-sharing system. In order to build lake and watershed data-sharing system, we select Asp.net as its web developing environment, Vs.net to build form application, and Sql server as its database. Thus, part of the code in client development is given. All in all, this paper draws the conclusion that smart client can be used in various data-sharing projects. Otherwise, aiming at the demand of data-sharing, it puts forward the draft of the system with smart client.