|Title:||Intranet/Internet GIS for town planning|
|Subject:||Geographic information systems|
Hong Kong Polytechnic University -- Dissertations
Department of Land Surveying and Geo-Informatics
|Pages:||vii, 114 leaves : col. ill., col. maps ; 30 cm|
|Abstract:||The popularity of the Internet and the advancement of information technology provide a good opportunity to develop the online GIS, a special GIS that uses the Intranet/Internet as a means to serve geographic data and the associated spatial capabilities. This dissertation is to investigate the feasibility for applying the GIS technology over the Intranet/Internet environment specifically for the applications related to town planning. The Planning Department (PlanD) of the HKSAR Government is selected as the pilot site for conducting the Feasibility Study. The prototyping approach is adopted to investigate the potential technical solutions for setting up the online GIS over PlanD's intranet. In the prototype, the architecture of a three-tier Client/Server design is adopted. It enables the diversity of the processing load on either the client-side or server-side and it also allows balancing loading on separate map servers. However, the data transmitted from map servers to clients in raster format limits the ways of designing, developing and applying the online GIS solutions. Due to the inadequacy of raster format in supporting GIS operations, the design relies on the server side to provide the majority of functionality. This solution may not be suitable for a government department such as PlanD which requires the handling of massive map data and various kinds of spatial analyses related to town planning. Delivering data in vector format may be one possible way out that allows users to take advantage of client-side processing in addition to server-side processing. However, one drawback of using vector format is that most of the vector formats employed by the existing Web-enabled GIS software packages are proprietary which require the installation of add-on compnents in client Web browsers. The development of online GIS applications in the Internet environment is similar to that in an intranet environment. The differences are mainly on the aspects such as system security and performance. As the Internet is considered as a public facility accessible to everyone, security measures must be set up in the Web system hosting the online GIS in order to protect the system from unauthorised access. This is an important concern to a govemment where data are essential resources that should be free from illegal intrusion. Another primitive constraint of the Internet is the stringent network bandwidth. The system performance of online GIS must be optimised in order to deliver quick responses to Web requests. To achieve optimal performance, the three-tier system architecture can be adopted to balance the system loading on several map servers. Moreover, sophisticated Spatial Engine can be introduced into an online GIS to speed up the system in processing geographic databases. The future development of online GIS largely depends on the official Internet and GIS organisations working co-operatively with data providers and GIS vendors to establish standardised data formats, protocols and architectures for online GIS. With the above-mentioned long-term goals achieved, it is believed that online GIS will become the mainstream in GIS application and it will eventually replace the traditional desktop GIS.|
|Rights:||All rights reserved|
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