Reference, completed project

ALARIC: the 1:250,000 digital regional geological map of Occitania

The ALARIC project, co-financed by the European Regional Development Fund (ERDF) and the National Fund for Territorial Planning and Development (FNADT), has produced a digital geological map of the Occitania region on the scale of 1:250,000.

15 November 2023

Geological map of Occitania

Thanks to the ALARIC project, BRGM geologists have been able to reconstruct the geological map of the Occitanie region. In doing so, they have been able to trace the extraordinary evolution of the region over more than 600 million years. The video shows you some emblematic geological sites and also explains how our geologists created the map.

A single legend for the whole region

Producing the map requires the creation of a single legend for the region, with 155 geological formations, from existing mapping documents.

To improve consistency on the scale of the map, it was also necessary to redraw its outlines.

The structural data have been synthesised to select, name and characterise about a hundred major faults from among the many faults in Occitania.

When finalised, the map will comprise 6 layers of geo-referenced indissociable vectors:

S_FGEOL: polygons representing geological formations
L_FGEOL: linear features representing seams
P_FGEOL: points indicating the presence of a remarkable geological formation
C_FGEOL: outlines of geological formations
S_SURCH: superimposition of S_FGEOL polygons to supplement the lithological data
L_STRUCT: linear features representing faults

The data and metadata used in creating the map comply with the Inspire Directive.