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Edit on GitHubGridded datasets
Gridded datasets are a known problem at GBIF. Many datasets have equally-spaced points in a regular pattern. These datasets are usually systematic national surveys or data taken from some atlas (“so-called rasterized collection designs”). Georeferenced occurrences are snapped to a central point
Most publishers of gridded datasets actually fill in one of the following columns: coordinateuncertaintyinmeters, coordinateprecision, footprintwkt So filtering by these columns can be a good way to remove gridded datasets. The R package Coordinate cleaner also has a function for removing gridded datasets. GBIF has an experimental API for identifying datasets which exhibit a certain about of "griddyness". You can read more here: https://data-blog.gbif.org/post/finding-gridded-datasets/
Absence records
By default, both presence and absence records are shown when you search www.gbif.org. Absence records confirm that a species was not found at a specific locality when that area was surveyed and this information can be useful in, for example, developing ecological niche models. However, you may only be interested in presence records and in this instance you can filter for only presence records using the Occurrence Status filter.
Establishment Means
The Darwin Core term establishmentMeans identifies the process by which the biological individual(s) represented in the Occurrence became established at the location. As such, it can serve as a useful filtering tool for identifying records that are outside of a species native range with accepted terms for this field being native, nativeReintroduced, introduced, introducedAssistedColonisation, vagrant and uncertain. Currently, GBIF records can be searched using the older vocabulary terms native, introduced, naturalized, native, managed and uncertain - https://rs.gbif.org/vocabulary/gbif/establishment_means.xml, and these will be updated in late 2022. In some instances, removing “MANAGED” records will remove zoo records.
Use this filter cautiously, however, as most records do not contain this information and so would be exluded from a search with this filter on. We would recommend to use the information within the Establishement Means term for filtering after download.