TEMPORARY & PRELIMINARY UPDATES IN ENCS
The use of T&P NM information is considered an essential part of keeping navigational charts up to date.
Most PRIMAR nations have included T & P NMs in their ENCs. Where this is the case, the ENCs are up-to-date, and therefore, no additional information layer is necessary.
According to the IHO, more member states have indicated that their T & P NMs will be included in their ENCs by 2015.
In order to inform the users about the status of production of T&P notices in the ENC update files, PRIMAR and IC-ENC have collected information from the individual HOs distributing ENCs through the RENCs.
The following link gives an overview of T&P NTMs ENC updating production status for each nation.
ENC cells require updating to include details published in paper chart Notices to Mariners. These are in two forms:
- Chart Correcting Notice to Mariners (NTM)
- Temporary and Preliminary Notice to Mariners (T&P NTM)
Not all ENC producers include T&P NTMs in their ENCs. As for those who do include T&P, there are several different practices:
- Some produce T&P according to their NTM
- Some produce T and not P
- Some produce P and not T
- Some produce T&P if considered necessary, case by case assessment
Previously, Annex B of the IHO standard S-65 provided guidelines for encoding T&P ENC updates. Recognizing the importance of adding T&P NMs in ENC updates, IHO incorporated those guidelines in S-57 Appendix B.1, Annex A in October 2011, resulting in the removal of guidelines from S-65 in April 2012.
The guidelines identify key principles for ensuring appropriate temporary and preliminary ENC Updates.
A new T & P survey was conducted in 2013 by IHO. The report Status of T-P ENC Updates presents the consolidated results of both 2011 and 2013 surveys.