Key:source:date

The key source:date=* is used to indicate the date when the source of information of anything added to the OSM database was taken. This tag is normally added to a changeset but has also been used on individual database objects, together with a source=* tag. Most uses are due to imports.

What date format should be used?

There is no standing recommendation as to the date format to be used. However, the international standard ISO 8601 appears to be followed by 9 of the top 10 values for this tag. The ISO 8601 basic date format is YYYY-MM-DD .

Looking at the top uses:

• 6th top use is "201011" (1.8% of all uses) - does this imply "2010/2011" or "2010-11" or "2010-01-01" or "20.10.2011" (was top used value with >55% of all uses)
• All other 50 top uses all appear to use ISO format dates (these are 2011-03-13, 2009, 2008, 2011-06, 2007, 2011-03-22, 2011-11-06 and 2010-09-17)
• From there down one see many variations including non-dates, such as the 10th and 11th top uses, "Amtliche Vermessung, Stand 20120423" and "Amtliche Vermessung, Stand 20100428", respectively.

See also

• source=* to indicate through which means the object's information was acquired (especially useful when the source's quality is uncertain)
• start_date=* to indicate the date when the feature was physically founded or opened or when its construction officially finished
• note=* to create a note to yourself and other mappers
• fixme=* to mark objects and places that need further attention
• survey:date=*
• check_date=*