Chart datum and ordnance datum - UK National Tidal and Sea Level Facility
Original (non-English) name
Acronym
Chart datum and ordnance datum - UK NTSLF
Citation
Abstract
Tidal levels on this site (and most published tide tables) are given as a height above chart datum (approximately the lowest level due to astronomical effects and excluding meteorological effects). The heights of chart datum (CD) relative to ordnance datum (OD, at Newlyn) in the UK are listed below. The values are usually negative indicating that chart datum is below ordnance datum.