Introduction to WebGIS

Internet-based geographic information system (GIS) is often called Web-GIS. This is mainly because most client applications use the WWW protocol. As technology advances, the client may adopt new application protocols, which are also considered as Internet GIS.
1. WebGIS is a product of the combination of web technology and GIS technology. It is a new technology that uses Web technology to expand and improve geographic information systems.
2. Because HTTP uses a C/S-based request/response mechanism and has strong user interaction capabilities, it can transmit and display multimedia data on the browser, the information in GIS is mainly the spatial data that needs to be presented in graphics and images. Users can query and analyze spatial data through interactive operations. These features allow people to use the Web to find the space data they need and perform various operations.
WebGIS is a product of the application of Internet and WWW Technology in GIS development. It is an optimal solution to achieve GIS interoperability. From any node on the Internet, you can browse the spatial data in the WebGIS site, create a Topic map, and perform various spatial information retrieval and spatial analysis.

Therefore, webgls not only has the functions of most or even all traditional GIS software, but also has the unique features that take advantage of the Internet, that is, you do not have to install GIS software on your local computer to access remote GIS data and applications on the Internet.ProgramTo perform GIS analysis and provide interactive maps and data on the Internet.

The key features of WebGIS are object-oriented, distributed, and interoperability. Any g1s data and functions are an object. These objects are deployed on different Internet servers and assembled and integrated as needed. Any other system on the Internet can exchange and interact with these objects.

Basic Features of WebGIS

WebGIS is an integrated global customer/server network system.

WebGIS uses the customer/Server concept to perform GIS analysis tasks. The task is divided into two parts: the server side and the client side. The customer can request data, analysis tools or modules from the server, the server or execute customer requests, and send the results to the customer through the network, you can also send data and analysis tools to clients for use.

WebGIS is an interactive system

WebGIS allows you to operate GIS maps and data on the Internet, using Web browsers (ie, Netscape, etc .) perform some basic GIS functions, such as Zoom, pan, query, and label. You can even perform spatial queries: for example, "Where is the nearest hotel or hotel?" Or more advanced space analysis: such as buffering analysis and network analysis. Using WebGIS on the Web is the same as using the desktop GIS software on a local computer.

Through hyperlink, WWW provides the most natural interaction on the Internet. Generally, web pages viewed by users through hyperlinks are static images and texts organized by WWW developers. Most of these images are fpeg and GIF files, so users cannot operate on maps, even simple analysis functions such as Zoom, pan, and query cannot be executed.

WebGIS is a distributed system
GIS data and analysis tools are independent components and modules. WebGIS uses a distributed system like the Internet to deploy GIS data and analysis tools on different computers on different networks, users can access the data and applications from anywhere on the network, that is, they do not need to install GIS data and applications on the local computer, as long as they send requests to the server, the server sends the data and analysis tool module to the user to achieve just-in-time performance.

One feature of the Internet is that it can access distributed databases and perform distributed processing, that is, information and applications can be deployed on different computers across the entire internet.

WebGIS is a dynamic system

Because WebGIS is a distributed system, databases and applications are deployed on different computers on the network and can be updated by administrators at any time, each user on the Internet will obtain the latest available data and applications, that is, as long as the data source changes, WebGIS will be updated. The dynamic link with the data source will maintain the current trend of data and software.

WebGIS is a cross-platform system

WebGIS has no restrictions on any computer or operating system. As long as users can access the Internet, they can access and use WebGIS without having to worry about what the operating system is. With the development of Java, the future WebGIS can be "Written once and run everywhere" to bring the cross-platform feature of WebGIS to a higher level.

WebGIS can access various GIS data and functions in heterogeneous Internet Environments

This feature is the future direction of WebGIS development. Accessing and sharing GIS data, functions, and applications among GIS user groups in heterogeneous environments requires high interoperability. Opengeodata interoperablity specificaton proposed by OGC provides basic rules for GIS interoperability. There are many problems to be solved, such as data format standards, data exchange and access standards, and OIS analysis component standards and specifications. With the rapid development of Internet technologies and standards, fully interoperable WebGIS will become a reality.

WebGIS is a graphical hypermedia information system.

Using the Web hypermedia system technology, WebGIS can link different Map pages through the hypermedia hot link. For example, when you browse a national map, you can click a hot link on the map to go to the corresponding provincial map for browsing.

In addition, WWW provides WebGIS with the ability to integrate multimedia information and centralize videos, audios, maps, and texts on the same web page, greatly enriching the content and presentation capabilities of GIS.