EPSG

Upgrade of EPSG Dataset data model

Following the publication of the revised ISO 19111 data model earlier this year, IOGP will be upgrading the EPSG on-line registry and support web site.

The initial upgrade will be made in October 2019. At this time two releases of the dataset will be made:

Except for the data model changes the data content of v9.9 and v10.0 will be identical.

On its initial release, the v10.0 registry with new data model at www.epsg.org will be missing some graphic user interface (GUI) functionality such as boolean searches and reports for component entities. This will be added before the end of the year. The October release will include export of SQL and GML to the new data model specifications and Well-known Text (WKT) in conformance with ISO 19162:2019 through both the GUI and the application program interface (API).

Currently the on-line registry (www.epsg-registry.org) and current support site (www.epsg.org) require separate log-ins. As part of the upgrade, www.epsg.org will become a single site containing the new registry and support with one log-in. Users will need to register or re-register for this new site.

The changes to the data model being applied to the v10 EPSG Dataset are:

  • Identification of dynamic datums and of CRSs based on these. For datums and CRSs affected by this change, there will be no changes to existing EPSG codes.
  • Addition of a new construct of ‘datum ensemble’. A datum ensemble groups together successive realizations of a datum as one. Some CRSs will be associated with a datum ensemble rather than a single datum. These will include the generic WGS 84 CRSs (EPSG CRS codes 4326 [geographic 2D], 4979 [geographic 3D] and 4978 [geocentric]). Existing EPSG codes will be unchanged.
  • Addition of a new CRS subtype ‘derived projected’. The term is from the ISO model and is consistent with other terms in the model, but is a misnomer. It is a CRS which is based upon an existing projected CRS, so ‘derived from projected’ would be a more accurate description. Many seismic bin grids are defined relative to a projected CRS – others are defined independently and later referenced to a projected CRS. Examples of both approaches will be included in the upgraded dataset.
  • Some CRS, datum or coordinate operation entities will be associated with multiple ‘usages’ – scope/extent (area) pairings.

Further details of the model changes may be found here.

For changes to relational tables with details listed by table, see here.

For updated epsg.xsd file (changes to GML schema), see here.

The v9.9 existing registry (www.epsg-registry.org) will continue to be run for some months using the current log-in credentials. However only critical data changes will be made.

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