Vector and raster maps of Belgium

The Geological Survey of Belgium (GSB) has compiled data on Belgian geology since its foundation in 1896. Geological maps, published one century ago, at scale 1:40,000 are hosted at the GSB. The majority of these maps (numbered from 1 to 226) was edited between 1893 and 1905 by the "Geological Commission", active during the period 1890-1919.The maps (numbered from 227 to 236), corresponding to the eastern part of Belgium, have never been published (figure 1) because the "Eastern Cantons" were not belgian at that time.

Belgium was the first country to possess such a complete and detailed geological map (In French: Boulvain F., 1993 - Un historique de la Carte géologique de Belgique - Prof. Paper, n°262, 88 pages).
Nine geological maps at scale 1:25,000 were published after the second world war by the "Geological Council" (1947-1977). They concern the Mons basin (Prof. Marlière) and a part of the "Stavelot Massif" (Profs. Fourmarier, Asselberghs and Geukens).

GSB and the geological cartography

In 1989, the Flemish Region (at scale 1:50,000) and the Walloon Region (at scale 1:25,000) started the realization and the publication of new geological maps corresponding to actual needs and geological specificities of each region.
The basic sources for this revision corresponds to data collected by the GSB and stored at the GSB that are always free for consultation. In this context, the geologists from the GSB have actively participated as authors and co-authors of the new maps, or as members of the "Geological Committee" that supervised the new geological campaign.

The development of computer technologies and geographical information systems permitted a more dynamic approach during the conception of geological maps as well as the possibility of permanent data updates. The geological cartography of the Flemish Region is finished in 2003 but the cartography campaign in Wallonia will continue for years due to fieldworks and the collection of geological data during systematic campaign.

The geological map at scale 1:40,000: a digital product of the GSB

One of the GSB missions concerns its own geological data computerization. Geological maps at scale 1:40,000 have been digitized; the rasters have been georeferenced, vectorized (figure 2) and assembled in one numerical geological map. Note that the definition of the vectorization procedure has been realized at scale 1:40,000 using a digitalisation table.

The geological map is a chronostratigraphic map and the original legend has been totally preserved. Every polygon of the vectorial map corresponds to a geological system, stage or other stratigraphical subdivisions. On the other hand, complementary information indicating local lithological variations as well as rock types (recognized by boreholes) are included on the geological maps. Each map has its own specific legend identical to that of the original document.

Digitalization is directly related to the scale 1:40,000. At a greater scale, a systematic deviation will appear between raster and vector maps. For this reason, we recommand the use of the vector maps at scale 1:40,000. It must be noted that the precision of these geological maps is linked to the cartographic projection in use during the publication of these maps at the end of the 19th century. Until today, the observed differences of the limits of similar cartographical unit between neighbouring maps has not been modified.

Computer data

Georeferenced and vectorized raster geological maps (version 1.2) are available for sale: for the whole country but also by packs of nine maps. This new version (1.2) includes final corrections and small bugs, a better juxtaposition between raster and vector data. The second version will be send for free to the buyers of the first version.

Raster files will be avalaible as ".tif" format with indexed colors at 150 dpi. The size of each raster file is around 3,4 MB.

Vectorial files will be available as ".tab" format for MapInfo users and ".shp" format for ArcGIS users.

Pack prices

You will find here the 4 packages of the product GIS-GEOLOGICAL MAPS on sale at the GSB: