Design and Implementation of WebGIS Based on Distributed Components

WebGIS serves as an important means of communicating, conveying and presenting geographical information and knowledge to the public through Internet. However, due to its technical complexity and inability of tailored functions, communities lacking the expertise and resources cannot make full use of this technology. This paper presents a novel development approach for WebGIS based on dynamical integration of distributed components technology, which is potential to overcome the problems. WebGIS applications developed with this approach can run at multi-mode, including stand-alone and network, and allows users to add expected GIS components to the system at run time. The mechanism of each working mode is explained and key technologies supporting the mechanism are discussed. To validate feasibility of the approach, a prototype called FreeXGIS is proposed, and the architecture design and implementation of several elementary components of the FreeXGIS are discussed in detail. It provides a paradigm for developing WebGIS applications by employing distributed GIS components. Also several future works to enhance the performance and practicability of WebGIS developed with this approach are presented at last.