Here is a selection of essential public portals for any documentary investigation before a construction project or a geotechnical study. These sites give access to regulatory data, official mapping and the archives of the French subsoil.
Géorisques
georisques.gouv.fr ↗
Official portal of the French Ministry for Ecological Transition that gathers all the information relating to the natural and technological hazards to which a plot is exposed: clay shrink-swell, underground cavities, earthquakes, floods, ground movements, polluted sites and soils, classified installations, former quarries, etc.
Geotechnical use: mandatory consultation before any G1 mission, automatic generation of the Statement of Risks (ERP) to be attached to property sales (ELAN law).
Géoportail
geoportail.gouv.fr ↗
National mapping portal of the IGN. Gives free access to official French mapping: topographic maps (1:25,000, 1:50,000, 1:100,000), current aerial photographs, cadastral parcels, land use, urban planning maps, contour lines, hydrography, etc.
Geotechnical use: basic tool for locating the site, assessing the topography, reading the context (urbanization, hydrography, roads, etc.). Built-in distance and elevation measurements.
InfoTerre — BRGM
infoterre.brgm.fr ↗
Mapping viewer of the BRGM (French Geological Survey). Gives access to the 1:50,000 geological maps covering the whole French territory, to the Subsoil Database (BSS) which lists more than a million boreholes, drillings, geothermal works and water points, as well as hazard maps (cavities, ground movements), mineral resources and aquifers.
Geotechnical use: the reference for identifying the geological formations in place, consulting neighbouring boreholes already carried out, and preparing the investigation campaign.
Remonter le temps — IGN
remonterletemps.ign.fr ↗
Map-comparison tool of the IGN that lets you visualize the evolution of a place over time. It compares, in two synchronized windows, old aerial photographs (1920 to today), the État-Major maps (1820-1866), the Cassini map (18th century), and current views.
Geotechnical use: an indispensable tool for spotting former quarries, marl pits, gravel pits, rubble, filled-in ponds, major changes in the natural ground, embankments. It also confirms the presence of cavities on old historical IGN maps before they are erased from modern maps.
USG — Union Syndicale Géotechnique
union-syndicale-geotechnique.com ↗
Official site of the Union Syndicale Géotechnique, the professional union that brings together geotechnical consultancies and companies in France. The USG publishes guides, recommendations and positions of the profession on geotechnical engineering practices, and intervenes on standards (NF P 94-500, Eurocode 7) and regulatory matters.
Geotechnical use: reference for good professional practices, access to USG guides (contractual annexes, methodologies, positions on the G1 to G5 missions, feedback), industry news and regulatory monitoring.
Bonus — a few other useful resources
- Centre Scientifique et Technique du Bâtiment (CSTB) — Technical Assessments and codes of practice
- AFNOR — Standards catalogue (NF, EN, ISO)
- Cerema — Technical studies on infrastructure, road geotechnics
- ADES — Eaufrance — National database for access to groundwater data (piezometry, quality)