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INSPIRE-MIF / gp-geopackage-encodings

Good practice for GeoPackage encodings of INSPIRE datasets
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Datetimes and time zones #1

Closed heidivanparys closed 1 year ago

heidivanparys commented 3 years ago

It is unclear in the GeoPackage specification whether datetimes may have time zone information, or datetimes must be UTC times. See also https://github.com/opengeospatial/geopackage/issues/530

What would the INSPIRE community like to have? Do we want to distribute are data with UTC datetimes, or do we want to have datetimes with a time zone offset? And for e.g. the EEA, as an organisation that puts data from different countries together, are there any implications? Feedback should be given to OGC if this is important for the INSPIRE community.

Additional note on datetimes: 2018-03-01T10:13:19 would be a local time (with the location unspecified) according to ISO 8601 (INSPIRE's default temporal reference system, see IR interoperability of spatial data sets and services and IR metadata) but would be UTC time according to SQLite. So when providing 2018-03-01T10:13:19 in a GML file that would mean local time (XML uses ISO 8601), and when providing 2018-03-01T10:13:19 in a GeoPackage that would be UTC time. Which may give interoperability issues when combining GML and GeoPackage data.

Update 2021-01-21: the OGC specification has been clarified.

heidivanparys commented 3 years ago

This issue has been closed in the GeoPackage SWG: UTC datetimes must be used.

heidivanparys commented 3 years ago

Note that the ETS for GeoPackage does not check the correct use of UTC datetimes (datetimes without time zone offset), see also https://github.com/opengeospatial/geopackage/issues/558 . Perhaps it should be considered to test this when/if an INSPIRE encoding for GeoPackage will be approved.

heidivanparys commented 1 year ago

This is not a GeoPackage specific issue, so I'm closing. Just be aware that the GeoPackage specification requires date times to be specified in UTC.