The Spatial Data Infrastructure for the Geological Reference of France
International audience ; As a continuation of the national programme of geological map of France at 1:50,000, the French Geological Survey (BRGM) engaged in the Geological Reference of France (Référentiel Géologique de la France, RGF). Over the next decades, this programme aims at developing a three dimensional knowledge of the eleven different geological regions through a continuous, homogeneous and consistent description permanently updated as well as understanding the mechanisms governing their evolution over time.All existing and newly acquired information, currently in the Pyrenees, are integrated within the RGF spatial data infrastructure (SDI). It provides the associated scientific programme with the necessary information system (data structure, computer means, applications and tools) to meet the various needs of contributors and end-users, from acquisition to dissemination of public data and knowledge. The RGF SDI must deliver the best available geological information over the territory, whatever the producer, i.e. research works, applied geology projects, both internal and external to the RGF programme. It must also abide by French and European legislation in terms of interoperability and open access to public data.The quality and reliability of the data and knowledge capitalised in the RGF SDI are primarily based on a thematic reference system including detailed lithostratigraphy, chronostratigraphy, structures and geological events. Both 2D and 3D geometries are also part of the references so that the RGF SDI can be used by other information systems e.g. hydrogeology, mineral resources and geohazards. This involves a dedicated architecture of data sets and applications as well as innovative data structures to capture the complexity of the geological objects and processes. A description-oriented method was used for building original master data sets from textual descriptions in natural language. For example, it was applied to lithology and also its transformation by diagenesis, metamorphism or ...