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OpenHistoricalMap logo.svg start_date:edtf
Dr Auguste Ferrier House, circa 1849 - Historical plaque (50534826781).jpg
Approximate or uncertain date when the feature came into existence. Show/edit corresponding data item.
Group: lifecycle
Used on these elements
may be used on nodesmay be used on waysmay be used on areas (and multipolygon relations)may be used on relations
Useful combination
Status: de facto

This subkey of start_date=* qualifies the feature's start date in the Extended Date Time Format, a profile of ISO 8601 that supports times of day, uncertainty, approximation, and seasons.

How to tag

Tag the EDTF start date in start_date:edtf=*. For backwards compatibility, also set start_date=* to the most accurate date that can be expressed in that key's more rigid YYYY-MM-DD format.


Software support

In iD, you can click the Add EDTF date button in the Start Date field to set an EDTF date. iD validates this date and will warn if it is malformed or the start_date=* falls outside the range of possible dates described by the EDTF date. If the start_date=* is expressed in OSM's "approximations" format, iD will flag it as an invalid date and offer to replace it with the equivalent start_date:edtf=* tag in EDTF format.

No renderer has built-in support for EDTF dates yet.

See also


  1. Optional.
  2. Pick the more likely date, or whichever one is less likely to conflict with other features in the same vicinity.
  3. 3.0 3.1 Set notation is more semantically accurate than the older interval notation for this purpose.

External links