Acronym for Geographic Information System: a very general term for indicating either a geo-relational database software, or the information stored in the geo-database, as well as the whole information system (data + software + hardware).
A tool running on a particular GIS platform which can export maps into JS-GIS format.
In JS-GIS, a theme represents a (usually) multi-layer map. User cannot customize the map appearence, but can change the current visible theme without changing map zoom and location. Themes are obtained exporting a map from the GIS system and cutting it in tiles according to the related zoom levels.
A rectangular (generally square) portion of a map of such a size it can be easily viewed on a web page. Tiles allow to split large maps into easily manageable chunks. They are indexed by row and column number and georeferenced, so that the JS-GIS engine can locate a tile containing a point given the geographic coordinates of that point.
JS-GIS © 2001, 2002 by Luca S. Percich (mailto:firstname.lastname@example.org)
Last updated: dec 26, 2002