1. Principle

This part explains the principle of WebGIS.

75% to 80% of the information in human activities is related to geospatial location. GIS (Geographic Information System) is a computer information that collects, processes, stores, manages, analyzes, and outputs geospatial data and its attribute information. system.

Since its birth in the 1960s, GIS has developed rapidly, its application has become more extensive and deepened, and it has gradually integrated into the mainstream of information technology. It is becoming a new growth point of the information industry and one of the main components of the geographic information industry with great development potential. Today, the application of GIS has become the highlight of my country’s national economy and social informatization construction, and has increasingly penetrated into various professional fields and people’s daily life.

With the development of computer technology, network technology, database technology and the deepening of application, the development of GIS technology presents new characteristics and trends. GIS has experienced the development process from stand-alone environment application to network environment application. The GIS application in the network environment has developed from the application of the client/server (C/S) structure in the local area network to the WebGIS application of the browser/server (B/S) structure in the Internet environment.

With the development of the Internet, WebGIS has gradually become the mainstream of GIS applications. Compared with the C/S structure, WebGIS has the characteristics of convenient deployment, simple use, and low requirements for network bandwidth, which lays the foundation for the development of geographic information services. In addition to being used in traditional government management fields such as land, resources, and environment, WebGIS is also promoting the rapid development of in-vehicle navigation, mobile location services, intelligent transportation, emergency and disaster relief, urban facility management, and modern logistics that are closely related to daily life.

The early WebGIS function was weak, mainly used for electronic map publishing, spatial query and simple spatial analysis. The traditional C/S structure GIS application, so there is a situation where the B/S structure and the C/S structure coexist, and the C/S structure involves a large amount of data transfer between the client and the server, which cannot be implemented on the Internet platform. large-scale geographic information services.

With the development of e-government and enterprise informatization (e-commerce), an information system system consisting of multiple geographic information systems is constructed, which crosses the traditional boundary of a single geographic information system and realizes the resources (including data) among multiple geographic information systems. , software, hardware and network) sharing, interoperability and collaborative computing have become key technical issues that need to be solved in the development of GIS applications.

This requires that the data analysis and processing functions of GIS be moved to the server side, and the functions of the server side can be invoked through Web Browser or desktop software on various types of clients (such as PC, mobile terminal) to realize the traditional C/S structure GIS. With the functions, the B/S structure finally replaces the application of the C/S structure, and the spatial information grid is constructed through the interoperability and collaborative computing between the GIS application servers.

• 1.1. Map and WebGIS
  • 1.1.1. The role of maps
  • 1.1.2. Application of Digital Map
  • 1.1.3. The role of open source GIS
  • 1.1.4. Application of MapServer
• 1.2. Basic concept of WebGIS
  • 1.2.1. Geographic information system GIS
  • 1.2.2. The development of Internet technology
  • 1.2.3. What is WebGIS?
  • 1.2.4. The basic characteristics of WebGIS
  • 1.2.5. The composition of WebGIS
  • 1.2.6. Advantages of WebGIS
  • 1.2.7. The method of selecting WebGIS development tools
• 1.3. Introduction to major open source WebGIS
  • 1.3.1. Free and open source software, open specification and open data
  • 1.3.2. Components of WebGIS
  • 1.3.3. Component product
  • 1.3.4. Stack Products
• 1.4. Principle and method of HTTP
  • 1.4.1. Different methods in HTTP
  • 1.4.2. Difference between GET and POST in HTTP