Research And Application Of WebGIS Based On MapGuide Platform

The features and the structure of WebGIS were described in this thesis, and then the components that constitute the MapGuide platform and how these components work together smoothly were described in this thesis too. Three methods to develop WebGIS application based on MapGuide platform were enumerated in this thesis. To specify the occasion that each method can be applicable to, the features of each method were provided in this thesis.The first method is totally based on script language to develop WebGIS application. The key features of the method that is how to use the default ASP objects to obtain the information that the user entered and push back the processed results were provided in this thesis. The usage of the SDF Component Toolkit in script language was described in this thesis too.The second method is to write user-defined ASP object with Delphi and create the user-defined ASP object in script language, so we can call the revealablc method that the user-defined ASP object provided. The second method has advantages for the speed of WebGIS application development and the run-time efficiency. The key features of the second method were provided in this thesis. First, we must analyze the system, so we can decide what the user-defined ASP object could do and what script language could do. And we must know how to pass parameters between user-defined ASP object and script language. Second, how to create user-defined ASP object and the methods that the user-defined object provided in Delphi was described in this thesis. Third, after the user-defined ASP object was written, we can create the object in script language, so we can call the method that the object provided and get the processed results. How to use SDF Component Toolkit to access the spatial date file in Delphi was described in this thesis.The third method is to create a WebGIS-structured, stand-alone Windows application with Delphi. This method is to provide the mold to the third method. The second method is script language driven. The third method is menu driven that is the common way in which most standard Windows applications run. Inthis part, how to access the spatial data file in a complex way by SDF Component Toolkit, not only to add, search and delete point-shaped map features, but also to add, search and delete polyline-shaped and polygon-shaped map features was provided in this thesis. In adding polyline-shaped and polygon-shaped map features, a new way to process the SDL files that contained the spatial data instead of processing the corresponding SDF files that contained the same spatial data was provided in this thesis. The SDL file is text file and the SDF file is binary file. After the SDL file was processed, we can use SDF Loader in the application to convert the SDL file to the SDF file that contained the same spatial data. The method to access attribute database by Borland Database Engine in a complex way was provided in this thesis.