UKHO charts to change to WGS 84 Datum

The UK Hydrographic Office is to transfer 310 Admiralty charts of Great Britain to a horizontal datum compatible with World Geodetic System 1984 (WGS 84) Datum. The transfer of the remaining charts of the British Isles will follow. The move will allow GPS users to plot positions on Admiralty charts without having to apply longitude and latitude shift values.

Admiralty charts of the British Isles will in future be referred to the current equivalent of WGS 84 Datum for Europe, the European Terrestrial Reference System 1989 (ETRS 89) Datum.

On completion of the programme it is intended to convert the charts of Northern Ireland, the Republic of Ireland and the Channel Islands.

The change of datum will be incorporated in relevant new charts and new editions, but many of these will contain only the change of datum and associated amendments, together with updating for Notices for Mariners.

To minimise disruption to chart users, the UKHO says groups of charts, such as those for approaches to a major port, will be published on the same date. The normal procedures for announcing new charts and new editions in Weekly Notices To Mariners will be followed, says the UKHO.

Areas due to be converted by the end of June 2000 include the River Clyde; the east coast of England from Great Yarmouth to Harwich; the Solent; and the area of the Irish Sea north and east of the Isle of Man. The eastern portion of the Bristol Channel is due to be converted by the end of the summer. The east and south coasts of England from the Wash to Plymouth, together with the approaches to Liverpool, should be completed during 2001, says the UKHO.

Contact: Patrick Nealon.

Fax: +44 1823 352304.