MapObjects, Databases, and Internet Connectivity

Author: Bruce Thomas
Organization: King County GIS Center

700 Fifth Ave Suite 2300
M.S. Key-IA 2300
Seattle, WA 98104
USA

Phone: (206)263-4564
Fax: 206-263-3145
bruce.thomas@metrokc.gov

The King County GIS Center WWW map server has multiple browser windows allowing users to navigate a map image and query public agency databases associated with map features. A drop-down list showing GIS layers on the map window identifies attributes in a data sheet window. This paper reviews the development of this map server design using MapObjects, MapObjects Internet Map Server (IMS), HTML, ECMAScript (JavaScript), Oracle, and Internet Information Server. In general, map servers are initialized with metadata about GIS layers, symbology, and available feature attributes before responding to browser clients. Each map server is supported by an ActiveX DLL developed by King County using Visual Basic 6. This DLL encapsulates the map server metadata in an object hierarchy along with MapObjects 2/IMS 2 functionality, ADO database connections, and HTML templates.