The occurrences of Alien Species in Europe results from extraction of spatial data coming from a network of Data Partners, on the basis of the species contained in the EASIN Catalogue.

The process of retrieving the data from the Data Partners is done through the EASIN Data Broker system, which is able to retrieve the species occurrences and related information (date, source) from different kind of data sources and store them in a normalized database structure.

Data are subsequently transformed by converting the harvested data to the EASIN Data Model through the following steps: Validation, Cleansing and Standardization, Geocoding, Mapping, Application of Quality rules and finally loaded on the Geodatabase (Datawarehouse).

EASIN-Lit also contributes to enriching the Geodatabase through screening the scientific literature and retrieving geo-referenced data.

Official Surveillance systems on Invasive Alien Species of EU concern set up by Member States to comply with the provisions of regulation 1143/2014 are also expected to contribute to the update of the EASIN geodatabase.

Data collected are then shown in occurrences maps at Country, grid 10x10 km, river basin district and marine ecoregion level, which can be downloaded and exported.