XSLT Templates for Thematic Maps

Abstract

Computer technologies are gaining ground in cartography. But support and implementation of the wide range of cartographic interpretation methods ranks among the weak points of most computer systems focused on geospatial data visualisation. This paper tries to fill this gap. It presents XSLT (Extensible Stylesheet Language Transformations) templates and their control file designed for generating some types of thematic maps (e.g. different types of choropleth maps or diagram maps).

The XSLT language was selected for the following reasons:

• Very good compatibility with all XML (Extensible Markup Language) standards, including the GML (Geography Markup Language) format for geospatial data description and the SVG (Scalable Vector Graphics) format for vector graphics description.

• XSLT is standardised by the World Wide Web Consortium (W3C).

• XSLT is strongly supported by many software products, e.g. XSLT processors, XML editors or web browsers.

• Applications created with XSLT can be multiplatform, modular, well-structured, and of course open.

The output of thematic maps can be presented on the Internet, because the maps are generated in SVG format wich is supported by the main web browsers (directly or by plug-in). Some examples of created thematic maps for temporal geospatial data were tested in the VisualHealth project. This project tests different methods of visualisation of geospatial data of healthcare.