Research On The Definition Of Distributed Heterogeneous Geography Model Based On XML

The research on virtual geographical environment mainly concentrates on the 3D visualization of geographical information and the search and query of geographical data at all times. However only a little focuses on geographical modeling and analysis. The existing mechanism process models in geography are developed independently by different groups for different requirements. They are distributing in different places of network. So how to define and manage these distributed heterogeneous models uniformly, and how to integrate into the virtual geographical environment system, still remain the problems to be solved urgently.Based on the geography model library framework, this paper studies how to define the mechanism process models, which needs not modify source code, and how to wrap models automatically, which needs not program code.This paper describes the model definition document framework which defines model data and functions based on XML DOM(document object model). Then it introduces the contents of the model definition DOM in detail, which includes the uniform data storage of geography models, the methods of parsing all kinds of models data, and the means of distributed invoking models. For automatic wrapping models, the paper provides extensible model definition document framework. If the user operates on the graphical interface correctly, the model definition document can be generated automatically. Meanwhile the document will be submitted into the geography model library framework of virtual geographical environment. Finally, the groundwater models are defined under the model definition document framework, and invoked under the geography model library framework. The experiment shows that the model definition framework is effective, universal and easy to operate.