BioFresh project

Member of the

Freshwater Information Platform

Data quality issues and quality control

Metadata quality control

All metadata that are submitted to the Freshwater Metadatabase are subject to a quality control regarding the completeness of mandatory fields. Before the metadata of a dataset is published in the Freshwater Metadata Journal it undergoes a thorough review process.


GBIF occurrence data were obtained in processed Darwin core format through web services. The responsibility for the data quality lies with the data provider and as such the data should not be modified. We did however perform a set of basic technical quality procedures, which we use for flagging specific records. These procedures include checking the coordinates, potential zoo/aquarium/farm specimens and fossil records. In doing so, we allow our users to easily filter out these entries if desired.

Suspect coordinates

This flag covers a range of checks. First of all, we check whether the coordinate values fall within the expected range, are not extremely high or 0,0. Secondly, we verify whether the country in the description matches the country derived from the coordinates. And thirdly, we also flag the occurrences falling in the sea/ocean outside country boundaries. (Notice that this latter flag needs to be updated in the current version of the portal.)

Potential zoo/aquarium/farm specimens

As far as possible, we check the records for certain keywords that suggest that the specimen is held or cultivated in captivity in a zoo, aquarium, farm,…

Potential fossil specimen

Similarly to the previous flag, we check the description of the records for obvious words that suggest that it concerns a fossil specimen.