Keywords: webmapping, topographic maps, interactive maps
Institute of Cartography, ETH Zurich
ETH Hoenggerberg, CH-8093 Zurich
The presentation shows how to present interactive topographic maps with high graphical quality (both for viewing and printing) using open standards and open-source software. Because SVG graphics can be structured and linked to attribute data it allows the display of corresponding attribute-data with mouse-over effects, querying of geographical objects, user-defined symbolization and personalization. As to enhanced topographic functionality, interactive topographic maps allow to define analytical hillshading-parameters along with various standard dtm- analysis, such as extracting profiles, calculating exposition, aspect and visibility. Map calculation may be done either on the server- or on the client-side, depending on computing power, data licensing issues and responsivenes.
The presentation also deals with optimization techniques to keep filesizes small and enhance data maintenance, while still keeping display quality high. Optimization includes the use of centralized symbol libraries, re-useable objects, style-sheets, path-optimizations and XML-entities. Topographic databases tend to get large. Webbased mapping systems therefore usually send a subset of the whole data. Because SVG is a text-based format any sql-compatible database along with the developers favourite scripting or programming language will do the job. A solution for open-source databases, such as MySQL or Postgres will be presented.
About the author
The author is currently PHD student at the Institute of Cartography, ETH Zurich - His interests are in webmapping, terrain representation and cave-mapping. He is experimenting with SVG since late 1999 and co-founded the "carto.net" project - together with Andréas M. Winter - to make SVG technology available and transparent to cartographers and GIS people. The author is also part of the conference organization committee.