Define1.WEB-GIS (Geographic Information System Network) refers to Internet-based platform, the client application software uses network protocol, the use of the Internet, geographic information systems. Generally multi-host, multi-database and distributed to multiple clients connected to the Internet, which consists of the following four parts: WEB-GIS browser (browser),
nike air force one, WEB-GIS server, WEB-GIS Editor (Editor) , WEB-GIS information agent (imformation agent).
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Profile Features (1) globalization, server / browser application (2) real popular GIS (3) Good scalability (4) cross-functional technology platform features key technologies Brief Introduction Define2.WEBGIS: via the Internet to publish geospatial data and applications, in order to achieve spatial data sharing and interoperability, such as GIS and business information, online query processing. WebGIS client using Web browser such as IE, FireFox. WebGIS is the use of Internet technology to expand and improve the GIS a new technology, the core is embedded in the HTTP standard GIS application system to achieve the space under the Internet environment, information management and publishing. WEBGIS can be multi-host distributed deployment of multi-database, through Internet / Intranet to achieve connectivity, is a server / browser (B / S) structure, the server to the client to provide information and services, the browser (client) have access to information and applications of space capabilities. WebGIS is the development of Internet GIS technology in the product. GIS functions can be expanded through the Web, to truly become a tool for public use. Any node from the Web, Internet users can browse the WebGIS site spatial data, producing thematic maps, as well as a variety of spatial search and spatial analysis, so that the GIS into millions of households. Features (1) globalization, server / browser applications worldwide, any node in the Internet WWW users can access WebGIS server provides a variety of GIS services, and perhaps even global GIS data updates. (2) real popular GIS explosive growth of the Internet, Web services are access to millions of households, WebGIS to give more users the opportunity to use GIS. Now popular WebGIS platform: ARCIMS; Mapgis IMS; Super Map IS; TopMap World; MapXtreme mature products at home and abroad. WebGIS can use a standard Web browser to browse, search, also available through browser plug-ins (plug-in), ActiveX controls and Java Applet for access WebGIS functionality, browser and plug-ins are free, and easy access to the largely expanded the range of potential users of GIS. While the previous GIS as high cost and technical difficulty, often a small number of experts have the professional tools, difficult to promote. (3) Good WebGIS easy scalability with Web services in a seamless integration of other information, you can create flexible GIS applications. (4) cross-platform feature WebGIS ago, although some manufacturers for the different operating systems (such as: Windows, UNIX, Macintosh) respectively the corresponding versions of GIS software, GIS software, but do not have a truly cross-platform features. The Java-based WebGIS can be done WebGIS framework, according to the present analysis, mainly in two ways: 1. WebGIS also called picture-like grid map, vector map can also be achieved, mainly through the VML 2. Based on the control of vector map. (ActiveX, Java Applet) that two development advantages and disadvantages. In particular, the control will be based on restrictions. Since Google Maps has been released, more and more popular tile-style maps! The basic characteristics of WebGIS 1) WebGIS is an integrated global client / server network system. 2) WebGIS application client / server concept to the implementation of GIS analysis tasks. 3) WebGIS is the interactive system 4) WebGIS is a distributed system 5) WebGIS is a dynamic system 6) WebGIS is a cross-platform systems integration point of view,
nike air force 1 high, so the current WebGIS has the following basic features: (1) transmission protocol uses HTTP. (2) the main computing tasks are executed on the server, such as mapping, spatial database query, spatial analysis. (3) client generally used to explain the general HTML browser. (4) the remote server to provide geographic information services,
nike air force 1, the WWW server as a crucial point of information access. (5) WWW common markup language used in the browser and the server information and communication between the GIS plays an important role, even if the future use of other data format or HTML markup language has been replaced by other, probably it will not change. Key Technology [1] Web GIS development and GIS technology, information technology and communications technology are inseparable. Many Internet networking technology can be directly transplanted in Web GIS systems. However, there are some key Web GIS technology itself must be addressed,
nike air force one high, such as high-quality data compression technology, broadband and high bit rate WAP technology, component design, GIS. With the popularization of broadband networks and accelerate the rapid development of WAP technology, Web GIS application areas will continue to expand. (1) space compression and decompression of data in the GIS spatial data will produce vast amounts of data transfer and storage issues, even the high-speed broadband network, nor can image a variety of scales on the World Wide Web free roaming,
nike air force one low, so the compression of spatial data is particularly important. In addition, management and use of spatial data, such as the establishment of the database images (images seamless roaming), online data distribution, data communication transmission and so require spatial data compression and decompression. At present, the wavelet theory can be applied to spatial data compression and decompression, making GIS data compression research focus. (2) Web browser based on WAP technology, the Internet is as narrow-band wireless network, network environment is not very stable, but which is particularly high technical content and, therefore, how to solve the client load is a key issue. The best solution is to strengthen the server side, while research has compatible, expansion and interaction to meet the requirements of the client Web browser technology. (3) database management of distributed Web GIS Web GIS data access technology now have CGI, Web server-specific APl, JDBC, Object Web 4 ways. Object Web is the latest generation of dynamic Web technologies, mainly Java / CORBA, and Active X / DCOM 2 种 competing technologies. Object Web through distributed object technology, allows the client to directly call the server, overhead, avoiding the CGI form a 2 ways are language-independent, and the component type. However, Active X / DCOM is currently only runs on Win 95/NT, while Java / CORBA cross-platform features, has a very prominent feature. Function [2] (1) space for distributed geographic information can access WebGIS worldwide through a variety of means to obtain a variety of geographic information. The existing language through digital image data into a WebGIS-based data, making data sharing and transfer more convenient. (2) GIS spatial query, retrieval and online processing using your browser's ability to interact, WebGIS can graph and attribute data query and search, and through interaction with the browser so that different parts of the client to manipulate the data. (3) spatial model of service provision in high-performance server applications of the model and method, by receiving user-supplied model parameters for fast calculation and analysis of the results immediately to return to graphics or text, etc. to the browser. (4) resource sharing on the Internet a wealth of information resources on the Internet, most of them have the characteristics of spatial distribution,
air force one low, the use of WebGIS organization and management of such information to provide users with a variety of spatial-based information services, and improve resource utilization and sharing level. Technical methods present, there are a number of different techniques were used to develop web-based geographic information system. They are: the public network side interface method (Common Gateway Interface-CGI), server application programming interface method (Server API), insertion (Plug-in), Java programming language, Internet, ActiveX technology and methods. Currently the main platform for building software webgis mapgis, arcgis, supermap other entries for more Atlas Atlas References 1
Liu Jifu, Zhang Fuping, Yang Xue Chao. WEBGIS and its application [J]. Jiangxi Meteorological Science and Technology, 2003, 26 (1)
2
He Yuanyuan, Zhang Ying. WebGIS development status and prospects [J]. Shijiazhuang Institute of Railway Technology, 2008, 7 (1).
Further reading: 1
http://www.handandaily.com/post/WebGIS.html
2
practice of geographic information systems spatial analysis tutorial
Open Category: Geographic Information Computer
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