CRS Well Known Text SWG


2.    Purpose of this Standards Working Group (SWG)

The purpose of this Standards Working Group is to progress the Well Known Text (WKT) representation of Coordinate Reference System (CRS) definitions to the state of an adopted OGC standard and an  identical ISO International Standard. This will be achieved by processing comments received during the public comment period and ensuring that the standard is consistent with the OGC and ISO TC211 business plans. The work will be conducted jointly with ISO TC211.

3.    Scope of Work

This SWG will deliver a modular standard for the self-contained and compact description of Coordinate Reference Systems and Coordinate Operations through simple Well Known Text strings. The implementation specification delivered will be consistent with OGC Abstract Specification Topic 2 (document 08-015r2) and ISO 19111:2007.
3.1       What is Out of Scope?
This SWG will not consider Well Known Text for representations of features other than CRSs and Coordinate Operations. In particular it will not consider WKT for geometry as elaborated in OGC 06-103r4, Implementation Standard for Geographic information - Simple feature access - Part 1: Common architecture.
3.2       Specific Contribution of Existing Work as a Starting Point
The starting point for the work will be the New Work Item Proposal submitted to ISO TC211 as TC211 document N 3383 (OGC document 12-102) together with comments received during the ISO ballot (TC211 document N3431, OGC document number TBD).
The abstract data model for spatial referencing by coordinates is described in OGC Abstract Specification Topic 2 (document 08-015r2) and ISO 19111:2007.
WKT is described in the OGC implementation specifications 99-036 through 06-103r4 and International Standard ISO 19125-1:2004, “Geographic information – Simple feature access – Part 1: Common architecture”. The WKT representation of CRSs was subsequently extended in OGC implementation specification 01-009 "Coordinate Transformation Services" and this extension was later adopted in the OGC GeoAPI 3.0 implementation standard.