7.1 Map data fields to Darwin Core

There are many possible ways of setting up your datasheets, and if you are new to OBIS you likely did not use standardized Darwin Core (DwC) or BODC vocabulary before samples were collected. In mapping your data fields to DwC we recommend documenting your choices so you have a reference to go back to should the need arise. In such a document you should take notes on the choices you made, as well as any actions you had to take (e.g. separate one column into many, convert dates or coordinates, etc.).

For example, a DwC mapping reference table could look like the following:

Verbatim field name	Mapped DwC term	Actions taken	Notes
date	eventDate	convert dates to ISO
coordinates	decimalLongitude, decimalLatitude	convert ddmmss to decimal degrees, separated one column into 2 for longitude and latitude	put original coordinates into verbatimCoordinates

In order to help you map your data to DwC terms, we have provided the table below which outlines some common data fields, their associated Darwin Core vocabulary, and which data table the field is likely to go in:

Common Raw Terms	DwC Field	Data table
Date, Time	eventDate	Event, Occurrence
Species, g_s, taxa	scientificName	Occurrence
Any biotic/abiotic measurements*	measurementType, measurementValue, measurementUnit*	eMoF
Depth	maximumDepthInMeters or minimumDepthInMeters	Event, Occurrence
Lat/Latitude, Lon/Long/Longitude, dd	decimalLatitude, decimalLongitude	Event, Occurrence
Sampling method	samplingProtocol	Event, eMoF
Sample size, N, #, No.	sampleSizeValue	Event, eMoF
Location	locality	Event
Presence, absence	occurrenceStatus	Occurrence
Type of record/ specimen	basisofRecord	Occurrence
Person/ people that recorded the original Occurrence	recordedBy	Occurrence
OrcID of person/ people that recorded the original Occurrence	recordedByID	Occurrence
Person/ people that identified the organism	identifiedBy	Occurrence
OrcID of person/ people that identified the organism	identifiedByID	Occurrence
Data collector, data creator	recordedBy	Event, Occurrence
Taxonomist, identifier	identifiedBy	Occurrence
Record number, sample number, observation number	occurrenceID (either ID or incorporated into ID)	Occurrence

Note that mapping abiotic/biotic measurement fields (sex, temperature, abundance, lengths, etc.) will occur within the extendedMeasurementOrFact extension. Here this data will go from being a separate column to being condensed into the measurementType and measurementValue fields.

The obistools R package also has the map_fields function that you can use to map your dataset fields to a DwC term.