The GEMAS dataset is based on low density geochemical sampling of agriculture (Ap) and grassland (Gr) soils across 34 European countries. Sample density covering an area of 5.6 million km2 of 1 site each, arable land (0-20 cm) and land under permanent grass cover (0-10 cm), per 2500 km2. The Geochemical Mapping of Agricultural and Grazing Land Soil comprises more than 70 chemical elements and parameters determined on more than 4000 soil samples. The geochemistry of European agriculture and grazing soils are depicted graphically on maps of the GEMAS geochemical atlas.

In 2016 the Geological Survey of Ireland as a European partner contributes to GEMAS and EGDI (European Geological Data Infrastructure) with provision of a GIS spatial data classification and publication of WMS geochemical web mapping services to support European data interoperability of EGDI web portal.

The GIS GEMAS sample classification were constructed in ArcGIS 10.1 and the original GEMAS dataset is available as ESRI shapefile format.