Frequently Asked Questions

This part of the documentation answers common questions about the Open Cultuur Data API.

What does date_granularity mean?

Dates are fickle things. A date is a particular point in time, and can be represented in very many ways. In addition, dates have gradations in precision. For example, Jan. 1970 is not as precise as 1 January 1970 00:00:00 is.

The different collections in the OpenCultuurData API expose dates with very different precisions (18th century, 1 January 1970, etc.), often because that is as precise as the collection owner knows. In order to be able to reason about these dates, we opted to generate a full-fledged date anyway (so Jan. 1970 becomes 1970-01-01:00:00:00), and store its granularity alongside it. The granularity signifies how precise the date is known; it is an integer, which indicates how many digits of the (IS-formatted) date were known.

Example date Granularity Description
20th century 2 20th century means between 1900 and 2000
1970 4 We know the year exactly, so we know the first 4 digits
January 1970 6 Month and year
1 January 1970 8 Day, month and year