Guidance Notes


EPSG Dataset Supporting Documentation


Using the EPSG geodetic parameter dataset (Guidance Note 7-1)

This document gives detailed information about the Dataset contents and its maintenance. It includes annexes covering Data Naming Conventions and Rules for Deprecation.

Coordinate Conversions and Transformations including Formulas (Guidance Note 7-2)

This document provides the formulas for executing coordinate conversions and coordinate transformations using the coordinate operation methods supported in the EPSG dataset. Geodetic parameters in the Dataset are consistent with these formulas.

EPSG Geodetic Parameter Registry – Developer Guide (Guidance Note 7-3)

This document is primarily intended to assist computer application developers in using the previous EPSG geodetic parameter registry service interface at to extract data from the old registry. This document has no relevance to GeoRepository. 

EPSG Geodetic Parameter Relational Database – Developers Guide (Guidance Note 7-4)

This document is intended to assist computer application developers in using the EPSG geodetic parameter relational database and SQL scripts. It may also be useful to other users of the data. Readers are recommended to have read Part 1 of the guidance note before this part.

Geomatics Guidance Notes

For all IOGP's Geomatics Committee reports, please go to IOGP Bookstore.



Guidance Note 7-1 (ver 8, Aug 2012)
Guidance Note 7-2 (ver 58, Mar 2020)
Guidance Note 7-3 (ver 3.2, Sep 2016)

Guidance Note 7-4 (ver 4, Apr 2009)

: Parts 7-1, 7-3 and 7-4 of these documents support the old data model and will be withdrawn in due course. Part 7-2 is is not impacted by data model changes. For an overview to the model changes see here.


News from Geodesy Subcommittee

Dynamic Coordinate Reference Systems

Following the release of updated GN25 Dynamic versus static CRSs and use of the ITRF and new GN26 Coordinate Transformations in the US Gulf of Mexico OCS, the Geomatics Committee has now delivered 
a video introducing the concept of dynamic coordinate reference systems. 

The video is shared under the same T&C as other IOGP Publications and can be reproduced in whole or in part provided (i) that the copyright of IOGP and (ii) the sources are acknowledged.