The International Association of Oil & Gas Producers (IOGP) has announced an upgrade to its EPSG online registry of geodetic parameters www.epsg-registry.org. The online registry now includes the facility to export coordinate reference systems (CRS) and coordinate transformation definitions in well-known text (WKT) format that conforms to ISO 19162.
From version 8.5.1 of the EPSG Geodetic Parameter Dataset, IOGP’s online registry allows users to export individual or multiple definitions of CRSs in WKT format.
Geography Mark-up Language (GML) remains the preferred format for complete CRS definitions, since it includes metadata describing the source and applicability of the CRSs and coordinate transformations. Such metadata cannot be included in well-known text.
The WKT format was developed by the Open Geospatial Consortium (OGC) to offer a compact machine- and human-readable representation of geometric objects. It included a rudimentary capability for succinctly describing the critical elements of CRS definitions. However, this WKT specification for describing CRSs was incomplete. As a result, application vendors developed proprietary extensions to the formal standard, and these differed significantly from each other. In effect, the standard became non-standard. The new version of well-known text for coordinate reference systems described in ISO 19162 and the equivalent OGC specification was jointly developed by OGC and ISO Technical Committee 211 to address this issue.