Jinsha river basin suffers from most serious soil and water loss among the six large watersheds in Yunnan province. To establish the Ecological Conservation and Construction decision-supporting system (DSS) in the river basin is of vital importance to the protection of resources and the local government's decision making through using the technology of GIS to capture, manage, analyze and apply eco-geographic information. This paper mainly discusses the application characteristics, architecture, and implementation of the project, namely, Jinsha River in Yunnan Province:Ecological Conservation and Construction DSS. Ecologists used to research the ecological status quo and transformation by measuring and analyzing with simple tools in paper maps and forms. But in ecological conservation and construction DSS, the GIS technology was introduced to overlay all kinds of eco-related information on 1∶250,000 and 1∶50,000 E-maps and TM images, spatial data and attributes data were uniformly managed to support decision for ecological conservation. Based on territorial ecological research, we developed and described an effective spatial analysis model for natural forest preservation by converting cultivated land into forest. The design and implementation of territorial ecological evaluation and forecast function was also introduced in this paper.

Digital landslide model is built supported by GIS in thi s paper Through spatial analyzing and three dimensional display, this paper analyzes the s tabilization of landslide and calculates the stability coefficient of landslide exactly and verifies the movement direction of landslide We bring forward the concept of the stability coefficient of landslide and research the method of calculating the stability coefficient of landslide and verifying the movement direction of landslide in three dimensional space We complete 3D dynamic study about the digital model and visualization of landslide's start up mechanism and landsl ide's movement rule Basing on those studies, we build a mathematics model to research landslide This model simulates and shows landslide motion process from static state to dynamic state The description of landslide is exactly quantitative in the digital landslide model Finally, we accomplish the 3D dynamic research and digital simulation under support of GIS.

Adapting to the need of Nandagang's wetland eco tourism, a software of Nandagang's wetland tourism information system (NWTIS) was specially designed and developed According to the idea of serving Nandagang's wetland eco tourism, integrating language editor and visual database management of Microsoft Visual Basic, with vector map output function of MapInfo, the authors have developed the NWTIS which realized query, analysis and display of a large mount of spatial and attribute data This paper introduced the details of design and development of the NWTIS, including the designing ideas, designing principles, development and application environment of the system,as well as design and development of its function modules,etc.

Based on data, information processing and analysis of digital Southeast Fujian by using GIS (geographic information system), implementation of digital Southeast Fujian and sustainable development of Southeast Fujian are proposed.As far as I am concerned ,"Digital Southeast Fujian" means the integration of cyber data with application and information sources for the purpose of realizing socialization of electrical information and intelligence in Southeast Fujian.

ComGIS,is components of geographic information systems,is composed of a group of GIS components which conform to the "technical criterion" of COM(Component Object Model) and is based on the platform of component objects and can be applied to all programming languages,furthermore various computers.One GIS component can communicate with another through standard communication interfaces. At present, it is a mainstream in GIS technology. Visual C⁺⁺, is VC for short. It is the heavy weight of programming language by Microsoft corporation with sufficient functions,being object oriented and visual.It is one of the most powerful popular programming languages at present, such as Visual C⁺⁺, Visual Basic, Delphi, etc. But the research on the development of ComGIS is rarely carried out in VC⁺⁺ programming language. The paper gives an example of the development of ComGIS in VC⁺⁺. The map data is from the Shiyanghe river basin which is a typical inland river basin in northwestern China. The fundmental functions of GIS, such as built-in of GIS components, zoom, pan and refreshing of a map and so on have been discussed. The research in the paper gives scientific and referenced bases for the development of ComGIS based on VC⁺⁺.

Travel activity is a typical process in which the flows of the tourists,the material and the capital are induced by the flow of tourism information. The essence of the Tourism Information System (TIS) lies in the inducing and controlling of the other flows by tourism information flow. The Internet constructs a universal framework linking up the global information flow. To simulate the interactive mode between the above flows of the tourism industry,the best platform is Internet and Geographical Information System (GIS). The characters of the tourism information and their corresponding requirements to the system platform were listed (Tab.1). In the paper,the traditional TIS is divided into four subsystems as Hotel Information System,Travel Agency Information System,Destination Information System and Computer Reservation System,and each of the subsystem’s frame mode is summed up. The most critical defect of the present TIS is that its information flow is split. TIS must be focused on the management of information flow and its structure should be designed to ensure extensive and steady flow of the tourism information. To provide decision support to the user,the interactive mechanism between the factors in the tourism flow system must be worked out and the specific spatial analysis function and multimedia geographical information expressing function of WEBGIS should be recurred to. Combining the above analysis with the present status of our country’s tourism industry in the background of globalization,the paper developed an integrated framework of TIS based on WEBGIS (Fig.2).

In combination with the project of establishing cadastral information system database for Land Re-sources Bureau of Haiyan County,Jiaxing of Zhejiang Province,the paper discusses the importance and urgencyof the database,puts forward the fundamental requirements according to the construction,the running,the usingand the maintenance of the database.In the form of flow chart,the paper briefly introduces a sort of method toset up the cadastral information system database.Moreover,some key technical points such as the method of da-ta acquisition,hierarchical classification and encode of cadastral data,the design scheme of the database struc-ture are discussed in detail.The paper also researches some methods to resolve a series of problems in the pro-cess of development stage of the project,and summarizes the practical experience of project development aswell.

Before Qin Dynasty geography had a tradition of inspecting the nature and research the nature, and great success had gained. From Qin and Han dynasties, Chinese ancient geography lost this tradition, the first ancestor is Ban Gu in Eastern Han Dynasty. Dong Zhongshu in Western Han Dynasty advanced a theory of rejecting the Various Schools, monopolizing the Confucian School. It excluded or strangled other Various Schools,and destroyed a tradition of laying stress on nature in the Confucian School. Ban Gu wrote Geography Section of History in the Han Dynasty, in which he submitted to trend at that time,overlooked the tradition of laying stress on nature during pre-Qin period, vested the geograthy with other meanings, took record of establishment and evolution of administrative division in domination, and took mountains and rivers of natural knowledge as dependency, cause later Chinese ancient geography to follow the road of putting stress on evolution and textual research of geography, as well as recording the social history and the social condition. These gradually formed a Chinese traditional geography focusing on the study of historic geography, economic geography and evolution geography. This is a major break in geographical history of China between pre-Qin times and Qin and Han dynasties. This break directly affected the achievements of the Chinese ancient geography, making the Chinese ancient geography fail to evolve into modern geography.

With the improvement of urbanization level, a large amount of residential communities have appeared in cities and community intelligent management system has been introduced to residential communities. But there is few research cases on application of spatial information management system to manage spatial data,information query and location analysis in building digital community. The article mainly uses GIS and spatial database technology and Web GIS method by taking Huilongguan of Beijing city as an example to merge spatial information technology with traditional real estate management method so as to realize effective management and discusses the technical feasibility and major ways and method to realize the goal.By using spatial information technology it can realize spatial data management of digital community,location query analysis,virtual three dimension scene,attribution data management, etc. The authors designed reasonable technology route and research method and conceived spatial information as an important information resource that must integrate traditional real estate management method with application system, only for this it can play an important role in information system application.

Data organization is the foundation and precondition for GIS the building and development Changes in cognitive modes and cognitive means can generate different, results of cognition in the real world,i e , the layer based data organization and the feature based data organization The paper analyzes in detail the means of the layer based data organization from the point of view of cognition and computer, namely from the point of view of theory and technique The development of the former is limited by lots of shortcomings in essential So the means of feature based data organization got developed Its foundation is to classify the features Feature classification is based on the theory of cognitive classification and it must use the means of classifying the geographic information for reference The latter should be developed with the object oriented technique on the basis of the former But both of them answer the basic cognitive questions: where, what and when By means of analysis and comparison, the paper draws a conclusion that it is the key to implement the fourth generation GIS for the feature based data organization, which is a new direction in GIS development.

With rapid development of GIS in recent years, the trend of components GIS has become more and more popular But because of the encapsulation essence of the object oriented model, programmers can only use the interfaces to communicate with the object without knowing anything about the realization details They will get into dilemma when they encounter those functions that GIS components can not realize In this circumstance, the outgoing interface defined by the GIS components can be used to extend the GIS components to realize those functions This article will introduce how to use the outgoing interface to customize the symbols in MapObjects and illustrate the mechanism of the process Meanwhile, the article will also introduce how to add an outgoing interface when developing GIS components Finally, the article discusses the possible trend of this mechanism.

Internet GIS is one of the most important developing directions of GIS,to build a practical internet GIS system, we must resolve the key technology of multi-source spatial data integration in the internet environ-ment,and spatial meta-data services in the internet environment. Web Service is a new technology in distributed computing domain,and an ideal model to implement inter-operation of different systems. We first made researches on the structure of internet GIS based on Web Service by comparing different computing models and different internet GIS software system structures,and provided a solution to Internet GIS application integration based on standard protocols such as XML, SOAP. Then,we studied the inter-operation of multi-source spatial data in internet environment, compared different multi-source spatial data integration solutions such as spatial data conversation, spatial data directing reading,and provided a new idea in multi-source spatial data integrations based on Web Service. In order to discover spatial data quickly in internet environment,we need a spatial meta-data system,and set up the spatial meta-data service system based on Web Services. The result indicated that spatial meta-data service system should be an essential part in internet GIS system structure. Finally, we introduced a practical example of internet GIS application based on Web Service, Nanjing "Digital House Property" internet GIS system. It is a mixture structure of GIS system,which was built in B/S part using Web Service technology and effective result was gained.

Geological simulation is one of the most important methods in geological study. The geological problems belong to macroscopical and continuous problems. But,we could only get finite and discrete data of spatial swatch. We need to convert them to continuous and visual geological section plane or geological body by using some interpolation methods. We should use the geological data sufficiently to get more useful information for geological study,because it is very difficult to collect geological data and the collection expense is very high; so data interpolation is one of the more important issues in geological simulation and also one of the important technical methods in geological data processing. It is not only the core of geological simulation,but is also is the guideline for the interpolation method selection,namely，“Preventing distortion of simulation,improving the precision of simulation”. The selection of interpolation method in different geological simulations is determined by the complexity and levity of geological body and the special applicable range of existing interpolation methods. The method of interpolation which we chose affects the precision and reality of simulation directly. In this paper,we briefly introduce the principle and applicability of several major and widely used geological data interpolation methods in allusion to the complexity of geological data interpolation in geological simulation,and discuss the choice of geological data interpolation method in different conditions.

The most significant characteristic of precision farming is to fully consider spatial difference of farmland and to take various management measures at different sites, such as variable fertilising and variable irrigating. The purpose of precision farming is to gain maximum financial income at the expense minimum environmental pollution. The data needed for paddy rice precision farming include GPS data, field spatial data, sampling data, meteorological data, yield data, data on paddy rice growth condition, and expert knowledge on paddy rice farming. And information system should be designed and developed to manage and process these data. The system consists of attribute data management subsystem, field spatial data management subsystem, expert knowledge subsystem, remote sensed data processing subsystem and management decision-making subsystem. The system is developed based on component GIS tools by programming with Visual Basic.

Different terrain factors express the undulating characteristics and spatial variations of the true surface from different aspects. The relationships among them can play a key role in revealing the mechanism and development of the terrain and geomorphologic situation to a great extent. The relationships and their variance discipline between the terrain factors and mean slope are discussed in this paper via the Back Propagation model of Neural Network. Fifteen loess gully-hilly areas are selected as the test areas for experiment, and the relevant 1∶10 000 and 1∶50 000 map scale DEMs of high resolution and high precision are also selected as the basic data. The results show this method can effectively evaluate the relevancy of terrain factors on the mean slope extracted from DEMs at the two scales. It is hoped that this result can be helpful in evaluating the availability of the DEM scale applied, determining the relevancies among multiple topographical factors as well as selecting suitable terrain variables for different applications.

Most of China was unexpectedly attacked by SARS.In the process of oppugnning SARS,facing theoperation of the mass information about epidemic situation and SARS's distributing spatiality,to adopt SARS'sepidemic information system can help people better in monitoring,preventing and curing and early warming.Onthe other hand it is imperative to build the epidemic situation geographical information system.This article,inlight of the actual data of epidemic situation and the practise of system founding,summarizes the problem andexperience which met in the process of designing and founding.It briefly discusses the establishment of the epi-demic situation geographical information system by taking SARS's information system as an example.It also dis-cusses the characteristics of SARS's information system,the principle of design,the composition of the systemand the process of system ultimately establishment.

This paper addresses the notion of conventional and digital generalization, and conducts a brief review and evaluations for a variety of conceptual frameworks of generalization.And we point out that the generalization should be treated holistically, fully from a system viewpoint.In order to exactly describe the connotation and domain of generalization, the authors suggest a new term, Geo-information Generalization, to supersede map generalization.Furthermore, based on analysis of geographic information communication, we propose a new concept of Geo-information Generalization chain, which includes four parts i.e.,objective generalization, database (or model) generalization, cartographic generalization and induction generalization.Objective generalization occurs when we abstract a portion from the real world to define and build an original database (primary model).The main objective of the following database generalization is to control data reduction for various purposes.Then cartographic generalization is used to generalize spatial data for cartographic visualization.Finally, induction generalization takes place when we make inferences from interrelationships among features in the real world and the database, on the map.The four sections are closely connected and interacted to each other during generalization.

Grid will be the next generation technique of internet The research and development of GridGIS will bring substantial change to the traditional GIS application model and computation capability The center of GridGIS will be service oriented It will be an intelligent platform for providing integrative spatial information application services The GridGML(Grid Geographic Markup Language) will be the communication and conversation language of GridGML It makes it possible for the spatial information transferring, storage and communication among the middlewares, agents, systems, and system internal Based on the XML, architecture of Grid GIS, and GML version 3 of OGC, the GridGML is detailedly analyzed and designed.

The Grid refers to an computer network infrastructure that enables the geographical distributed computing resource,storage resource,network resource,software resource,data resource,information resource… etc, to be integrated into a logistic one. Grid technology as a new generational Web technology,will deeply influence the development of Geographic Information System(GIS), especially on Web based large scale GIS,which is the key component of digital city .The infl uence is fully analyzed from six respects in this paper,and some conclusion are listed in this paper. Grid computing technology provides powerful computing resource support for data intensive spatial analyses,which is the key function of GIS, especially in GIS based simulation fields,such as urban transportation sim ulation and atmospheric pollution simulation. Data Grid technology provides integ rated solution for the storage,analyses,management,movement of large scale spatial data,and Spatial Data Grid(SDG) is the most powerful style of National Spatal Data Infrastructure(NSDI). Grid technology also provides a new method for real time scene rending and large scale scene data storage in Virtual Reality Geograp hic Information System(VRGIS),which is very promising in Virtual Geographic Envi ronment(VGE) construction. VRGIS can be used in fields such as martial flight si mulation and virtual city So Grid technology will speed the multi dimension tre n d of the development of geographic information system.With Grid technology,we ca n solve the interoperability problem more easily,which includes data interoperab ility problem,semantic interoperability problem and system interoperability prob lem. The software development model by using agent components that quarter at gr id node to build up applicatonal software danamicly in large scale geographic i n formation system domain will deeply influence the menthod of geographic informat ion system applicatonal software development. Finally,we advice to boost the dev elopment of the geographic information system industry by building up National S patial Information Grid(NSIG),which is the most important part of digital city. All in all, Grid can provide integrated geographic information application and/o r services for geographical distributed users at different organizations as if i t were a super WebGIS.

Most of the geographical information systems are based on the static data model but with restrictions when they operate with dynamic information. Only the current status of an entity will be kept and the historical data will be lost during updating because the current GIS data model is lacking ability in tracking the evolution of an entity. We only know what it currently is, we know nothing about its past. The current data models that nowadays GIS use are nothing but snapshot data models.With the widespread use of GIS in many related geographic fields, people begin to realize that GIS should have ability to describe the spatiotemporal changes that are taking place every day in our world, so historical analysis could be achieved and even future evolution trend of phenomenon could be predicted. This idea brings forth the concepts of Spatiotemporal Geographical Information System(STGIS) and spatiotemporal data model(STDM).This paper reviews the progress that has been made in spatiotemporal data modeling. Related concepts have been introduced in details, technical issues in spatiotemporal data modeling and STGIS have been analyzed. Two main kinds of spatiotemporal data models are discussed, namely version-based spatiotemporal data models and object-oriented spatiotemporal data models. This paper points out that lack of a perfect spatiotemporal data model is a main obstacle in STGIS development and the basic requirements for a spatiotemporal data model has been investigated from system aspect and design aspect. Historical retrospect and time sequence description ability are the most essential ones among these requirements. This paper concludes that in spatiotemporal data modeling, object-oriented modeling method should be used and the implementation of such a spatiotemporal data model should be based on state-of-the-art database technologies.

Urban land is the base for urban social and economic development. The variation of urban land-use structure brings different economic,social and environmental benefits to urban areas. At present,the land-use structures of most of the cities in China are,more or less,irrational. This has restricted the development of urban areas and the process of urbanization. For improving the level of intensive land-use,optimizing the structure of urban land and realizing the sustainable development of urban areas,this paper carried out a tentative study on urban land optimal allocation. Supported by RS and GIS,the suitability evaluation of urban land was implemented. And then,the optimization of quantitative structure of Jinan’s urban land was completed using a system-dynamics model established by us. Finally,the spatial allocation of Jinan’s urban land was performed automatically by a module developed using AML. According to the simulation results,the land use structure and the distribution of each kind of urban land use type will be optimized evidently,which is mainly characterized by the decrease of the land used to industrial production and its distribution shifted to the urban periphery. This paper integrated the AHP,systematic dynamics and land suitability evaluation with the optimal allocation of urban land use,which formed a framework for relative studies and have positive meaning to research of the pattern of land optimal allocation at the regional scale.

This paper describes the Nanji Islands Marine Natural Reserves Information System(NMNRIS)ofChina.The system is developed specially for Nanji Islands using RS,GIS and Database techniques.In NMNRIS,spatial database,remote sensing information database,shellfish and alga database and so on are established,andthe system has the functions of managing,updating and querying.In the paper,four sections are included as fol-lowing.(1)The first section describes the framework of the system,which is designed based on the analysis of theusers and their requirements.The system includes two sub-systems of spatial data and property data respective-ly.(2)In the second section,the data of the system are introduced.There are seven sub-databases in the sys-tem such as geo-database,remote sensing database,shellfish and alga database,document database,multimediadatabase and so on.(3)The functions of the system are discussed in detail from two aspects in the third section.The first func-tion is to manage spatial data and to do spatial analysis,and the other one is to manage property data.(4)Finally,the land covers analysis based on the system is discussed as an application of NMNRIS.Theresults obtained from the present investigation are as follows:(a)The main land cover types in the Nanji Islandare meadow,shrubbery,farmland,village,water body and sands.Meadow and shrubbery are the dominant types,being 89.6% of the island's total area.(b)The patch number,fractal dimension of the patch and patch perimeterare related to patch areas.The patch number decreases with the increase of the patch area whereas the fractaldimension increases with the increase of the patch area.The patch perimeter has the linear relation with thepatch area.(c)The fractal dimensions of the meadow,shrubbery,farmland and village calculated by the perime-ter-area method are 1.3433,1.3728,1.2563 and 1.2156 respectively.On the other hand,the fractal dimensionsof the meadow,shrubbery,farmland,village,water body and sands computed by the measure-perimeter-areamethod are 1.096,1.102,1.05,1.062,1.002 and 1.047 respectively.Thus,it is concluded that the meadow andshrubbery have higher dimensions compared with those of the farmland and village.It is indicated that patchstructures of the meadow and shrubbery are more complex than those of the farmland and village.Studies alsoshow that the fractal characteristics of land covers are related to the human activities.(d)The test of significanceof fractal characteristics shows that the differences between the meadow and shrubbery and the farmland andvillage are significant whereas the difference between the meadow and shrubbery and the difference betweenfarmland and village are insignificant.In a word,NMNRIS will improve the management level of the Nanji Islands Marine Natural Reserves.Atthe same time,the experiences and techniques of the project will lead the way for other similar projects,afterall,NMNRIS is the first application of RS,GIS and database techniques for Marine Natural Reserves.

Hyperspectral remote sensing technology is one of the most important leading fields in remote sensing which is paid more and more attention in the world. The successful launch of Hyperion in November 2000 provided a new and useful tool for remote sensing applications. Hyperion imaging spectrometer has the highest spectral resolution in orbiting satellites,and shows great application potential. Taking Subei district,Jiangsu province as a study area,this article analyzed the characteristic of EO-1 Hyperion data,studied the general method and procedure of calculating the spectral value of image from its grey value,selected 15 kinds of typical object samples and deduced their spectral curves in wavelength ranging from 400 nm to 2 500 nm. The feature of objects can be seen clearly from deduced spectral curves. Since the imaging time of the data was in late winter (10:19 am,January 15,2003),the vegetation withered and no typical spectrum characteristics of vegetation were displayed in visible wavelength. But in near-infrared region there was still a high reflecting peak. In short wave infrared wavelength,the reflection value is lower than that of near infrared because of the influence of water absorption. At the high tide time,the difference between river water and seawater was evident. The reflectance of seawater was much higher than that of river water because the seawater contained more mud and sand. The reflection value of turbid water is lower than that of clean river water in green wavelength and higher in red and infrared wavelength. Probably this is caused by the higher content of organic material and algous vegetation in turbid water. In salt field,the spectral reflection values of depositing pool,evaporation pool and crystal pool rose in turn with the increase of salt amount.

Fundamental Geographic Information is the framework and carrier of geo-spatial information and other information in information era, and is the important information fountain of scientific decision-making in the national sustainable development and the government's information and network construction. Based on the construction of fundamental geographic information in Hunan province, the paper analyzed the application of fundamental geographic information, and pointed out the main problems among the construction of fundamental geographic information:(1) the role of fundamental geographic information is not lay store by fully recognized by department concerned,, (2) the investment in the construction of fundamental geographic information is low, and (3) the skilled and technical personnel engaging in GIS industry is lack. It then put forward the service strategies and share mechanism in fundamental geographic information construction, and finally rendered the main projects among the construction of fundamental geographic information in Hunan province.

Universal Soil Loss Equation (USLE) is an empirical model widely used in the domain of soil erosion by water. Although USLE has a simple structure, the result of the model can reach the requirement for soil erosion prediction under certain precision with less input data. The improvement of USLE includes the expansion of application scope, the enhancement of suitability, and the improvement of estimate precision. There are two developing trends of USLE, one is traditional way, which enhances the prediction ability of USLE through introducing new applicable parameters or optimizing parameter values without modifying model structure. The other is nontraditional way, which makes more flexible and reasonable confirmation of factors as well as more valuable and ascertainable result of soil loss quantities by using fuzzy logic or artificial neural networks to modify USLE structure.

With GIS data processing, the historical records of county boundary, population distribution, farmland statistics and cultural phenomenon in Shaanxi Province during the Qing Dynasty were transformed into digital database which is composed of the GIS analysis platform for further study of the man-land relationship during historical period.For county level historical boundary, there are several guidance to follow, such as the records of major rivers, towns and residencial areas; the compilation of ancient maps; the watershed divide, etc. For the population distribution data, the number was linked to the county's name, and with the careful evaluation, the data on each county of Shaanxi province in the late Qing dynasty was credible for GIS processing.For the farmland records, the unit of mu(one mu equals to 1/15 ha) is a variance in different regions. While,there are only the raw records for processing, from which, reasonable analysis could be achieved with local geographical ideas.

Map is one of the important means of space information spread.The quantity of space information not only is big and complicated, but also increases steadily.Therefore, to reflect the big and complicated space information on limited map,cartographers have to reflect the main and essential aspects and throw away the subordinate aspects , for the legibility of map.This process is referred to as map generalization.In the process of automatic map generalization, river generalization is an important constitutional part of map data handling.Along with map scale variations , some double line rivers on the large scale maps have to be expressed by using single line rivers on the small scale maps.That is to say that in the automatic river generalization there exists a process of converting a double line river into a single line river.That is to bring up the inside stalk line from the double line river.Moreover, while establishing the river system's tree construction, the simplification from the double line river to the single line river will make it more convenient to establish the river construction relationship.The skeleton line for the construction of Delaunay triangulation net has one dimension characteristic which is brought up from two dimensional space.It has the nature of equally divided part of district.Therefore it is appropriate to bring up the stalk line inside double line river by establishing the skeleton line of Delaunay triangulation.In the automatic generalization process of river system, along with the contracting of scale, it is important to transfer attention to the characteristic of whole river net.Among them the main point is to keep the relative density and difference of river net.So, it is necessary to know the distance between near by rivers.But it is not easy to know the distance.Because of the complexity of the river curve shape the measuring calculation of the distance is difficulty and the results vary from person to person.The paper also researches the method for measuring calculation of the distance between nearby rivers by using the Delaunay triangulation.

This paper describes the system Architecture of ArcIMS,and its operational mechanism, particularly analyzes the role of Arc XML in this system Architecture It then discusses how to run Arc IMS and how to communicate between the client and server as well as the functions of ArcXML in this Architecture emphatically Meanwhile the logical and physical layers of Server are introduced and the core of ArcIMS is discussed The functions of every layer are described in detail The basic functions of Client are also introduced from the point of view of uses,and the feature service and the image service are analysed emphatically Then ArcIMS Manager is introduced and how to manage the ArcIMS Server is also introduced,and the three functional models are described separately Finally,the securities of Website are analysed combining the characteristics of ArcIMS itself Through data security and sevice security and system security the security of Website is discussed in detail,and the methods of how to resolve the security of Website are provided.

Based on the application of Grid Computing on Geographical Information System (GIS), this paper analyzes and expatiates current application of Grid Co mputing on GIS and the problem it faces With Middleware technology, it presents the architecture of Grid GIS and lists the techniques it needs After analyzing the common problem and the development of Grid GIS, this paper points out that the distributing architecture, which is based on GML internet language and Web Service technique and Middleware,is a main developing direction of current GIS software and the best way to solve the problem it faces, then we discuss its realization process.

First of all, supported by 3S technology, combining field investigations with indoor synthetic analysis, the types and area of wetland in Beijing were investigated and monitored.There are quite a number of types of wetlands with relative wide distribution, remarkable environmental difference and abundant bio-diversity.The main wetland types in Beijing include lakes, rivers, reservoirs, ponds, paddy fields etc., among them the area of artificial wetland is about 323 541.822km², and that of natural wetland, about 138 214.740km², accounting for 0.3% of the whole Beijing′s area. Secondly,dynamic change studies aiming at key reservoirs and typical wetland were made. The result of study shows that among the reservoir wetlands, the area of Miyun reservoir, Guanting reservoir and Huairou reservoir reduce separately 42.0%,23.9% and 4.9% compare with that of 1998 and changes of the landscape patterns of typical wetlands also take place correspondingly. It thus can be seen that the wetland area reduces and ecoenvironmental quality drops year by year in Beijing. Finally, we propose some constructive conclusions and suggestions according to current situation and problems existing in Beijing′s wetland. Thus the accomplishment of this scientific research item has laid the foundation for the further studies on the connection of wetland changes and climate, terrain and landforms, land use, vegetation change along with socio-economic development in the marginal area, and further analysis of the factors threatening the wetlands, evaluation of the current situation of ecoenvironment of the wetlands and putting forward measures protecting the wetlands in Beijing.