170 Our goal is to allow end-user to easily create, visualize, analyze and share web based thematics maps of its own arbitrary geographical business data. In order to achieve this, we developped a system centered on a XML description of data resources, thematic maps contructions and representation options. This system provides the end user a set of nested base maps (e.g. city, districts, regions boundaries), which are the foundation of the user defined thematic maps as part of a join with user data. Each registered user has its own data space in which he can describe and upload data and construct thematic maps. Technically speaking, the XML resource representation is accessed by PHP routines and XSL stylesheets for web pages construction, Cartoweb+Mapserver configuration files and PostgreSQL/PostGIS database queries. It is important to notice that the XML representation we developped for this application is independant of implementation choices (Mapserver, PostgreSQL, Cartoweb) and can be used as an API by any application to produce easy webmapping. FOSS4G2006 - Free And Open Source Software for Geoinformatics Session6 : Webmapping - LBS laurent pierre mail@lespierre.org franck martin franck.martin52@wanadoo.fr laurent pierre mail@lespierre.org <MaKaC.conference.ContributionType object at 0xb3c093ec>