In the modern geographic information systems, COTS software has been playing a major role. Customizing COTS software is inevitable because large organizations\u27 needs usually exceed COTS built-in functions. However, this is often a challenge to COTS users, since the source code of COTS is rarely available. In my thesis project, I have enhanced some functions of a GIS COTS product, ArcIMS, by taking advantage of this web publishing tool\u27s well-thought architecture of services and its applications of the XML messaging technology. Multiple users now can access the same ArcIMS map service but with only constrained viewing power. Login dialog has been added to the map service, and query tools have been modified to ensure the viewing restraint. Another aspect of this thesis project is to enhance the interactive features, which makes the HTML viewer be capable of carrying out all the functions that the ArcIMS Java plug-in viewer can do
