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Darwin Core

Term name



The verbatim original representation of the date and time information for an Event.

Apple Core




Verbatim date

The verbatim date is the collection date as written on the specimen label (see the definition for verbatim) and is recorded in a single free-text field.

It is recommended to have a verbatim date field in your database, as it is the most objective way to record the collection date and in some cases the only way to do so. You can either always populate this field or only when the formatted date cannot unambiguously represent the collection date (see examples).

Publish the verbatim date in verbatimEventDate. Remarks or notes regarding the collection date are accepted in this term as long as the verbatim date is included as well: "3/5/2009 (probably March)" or if the date is illegible: "illisible". If a database contains verbatim and non-verbatim dates in one field or if it is unknown whether the field corresponds to the verbatim date, it should not be considered a verbatimEventDate and should be shared in eventDate instead (see example 8). Transform those non-verbatim dates to ISO 8601 if possible (see below).

Formatted date

As the verbatim date doesn't readily allows calculation and sorting, most collections (also) record the collection date in a structured format. This can be done in numerous ways:

  • Date = 1980 Jul 8-15
  • Date = 7/8-15/1980
  • Date = 8-15/7/1980
  • Date = 8-15.07.80
  • Date = 8-15 VII 1980
  • Date = 1980-07-08/15 (recommended)
  • Date = 1980-07-08/1980-07-15 (recommended)
  • Start date = 1980 Jul 8 | End date = 1980 Jul 15
  • Day = 8-15 | Month = 7 | Year = 1980
  • Start day = 8 | Start month = 7 | Start year = 1980 | End day = 15 | End month = 7 | End year = 1980

It is recommended to store any formatted date using the ISO 8601:2004(E) standard. In ISO 8601 date and time values are organized from the most to the least significant and with a fixed number of digits per value: YYYY-MM-DD. Date ranges are expressed with a forward slash: YYYY-MM-DD/YYYY-MM-DD, YYYY-MM-DD/MM-DD or YYYY-MM-DD/DD. Partial dates can only be expressed by dropping the least significant values first: YYYY-MM or YYYY, but never MM-DD. For more information and examples, see Wikipedia and the Darwin Core wiki.

If it is necessary to record the collection date in multiple fields (start/end date or day/month/year), try to store the date in a format close to ISO 8601, so it can easily be transformed by concatenation.

Publish the formatted collection date in eventDate. It is highly recommended to use the ISO 8601:2004(E) standard, as it allows the date information to be shared unambiguously. Other date formats should only be used if the collection is unable to record or transform the dates to ISO 8601.

Although date ranges can be expressed in eventDate (with "/"), multiple dates cannot (see example 7).

Controlled vocabulary

It is highly recommended to use the ISO 8601:2004(E) standard:

Usage examples

Ideal situation

The following examples show the most ideal situation: the verbatim date is known, the eventDate is strictly expressed in the ISO 8601 standard and other date terms can be populated automatically.

Example # verbatimEventDate eventDate year month day
1 1 juillet 1991 1991-07-01 1991 7 1
2 1991-07-01 1991 7 1
3 3/1/2004 2004
4 Early spring 1999 1999
5 March 12 3 12
6 July 24-25, 1947 1947 7
7 May 16 and August 7, 1991 1991
  • Example 2: The collection does not record a verbatim date if the collection date can be unambiguously expressed in a formatted date.
  • Example 3: If additional information is available regarding the month (January or March), the terms can be populated as in example 1.
  • Example 5: Partial dates can only be expressed from the least to the most significant in eventDate. In this case the most significant (year) is missing.
  • Example 6: The eventDate may also be written as 1947-07-24/25.
  • Example 7: Some herbarium specimens have multiple dates (e.g. one for the flower and one for the plant). Multiple dates cannot be expressed in eventDate.

Least ideal situation

The following example shows the least ideal situation: the verbatim date is unknown, the formatted date is not recorded as ISO 8601 and it is not feasible for the collection to transform the formatted date to ISO 8601 for some of its records.

Example # verbatimEventDate eventDate year month day
8 01 Aug 1991

Other resources