Geological mapping is a core mission at LNEG. The in-depth knowledge of the geological infrastructure of the emerging and immersed territory, transcribed in geological mapping of universal use is the fundamental principle for the planning and the sustainable development of the territory. To this end, LNEG conducts and promotes systematic geological surveys of the territory at various scales, using the latest models and innovative techniques, such as remote sensing, GIS systems, palynological and absolute dating among others, geophysics, etc.

Geological mapping summarises the geological knowledge of a given region. Its interpretation allows the elaboration of 3D models and reconstruction of the probable geological history of the region, through the understanding of the geological processes that have taken place and is an essential contribution to the recognition and identification of geological resources and geological hazards, contributing to land use planning and nature conservation. LNEG also has a mission to inform public and private entities about correlated issues.

LNEG has geological maps published at several different scales: 1: 1 000 000 maps; 1: 500 000 and 1: 200 000. The Geological Map of continental Portugal in the 1/50 000 scale is the most used in terms of management and organization of the territory. It comprises 175 sheets, of which 78% are published. The Geological Maps of the Autonomous Region of the Azores and Madeira at 1/50 000 and 1/25 000 scales; geological maps to other scales, such as Lisbon, Algarve and Natural Parks. LNEG has collaborated in the publication of the Geological Chart of Spain and Portugal at the 1/1 000 000 scale, as well as in several maps of African countries, namely Angola, Guinea-Bissau and Mozambique.