CgiMapScript: Spatial Data and the Common Gateway Interface - Using Lightweight ISP-friendly Techniques to Handle Vector Data on the Internet

Key words: Internet, Vector Data, Cartography, Common Gateway Interface

The paper covers five years work on what seems to be the only attempt of its kind to achieve vector data driven web mapping employing:

• data compression
• object-oriented server and client-side spatial modelling
• spatial indexing
• mixed algorithmic multi-modal routing
• rule and fuzzy logic based theory
• spatial query handling WITHOUT a "GIS" application or server in sight
• "hit-then-quit" CGI map data handling scripts

The outputs are fast interactive internet maps embedded with URLs for both map and web content navigation, served as either GIF images with HTML overlays or Java Applets. Spatial algorithms such as routing "nearest," geocoding, etc., can be handled. Spatial object data is extracted from a GIS and pre-processed for compression and indexing - some data sets allow up to 94% shrinkage while maintaining full navigable topology.

The research is an accidental spin-off from Kingston's work on multi-modal public transport routing and was developed as a way to do mapping over the web within the constraints of a "normal" web development environment, and as such offers a way for much wider accessibility to vector cartographic data sets in that they can be handled easily as a standard data type by these techniques.