newlyn datum
LowTechnical/Specialized (Geodesy, Cartography, Surveying)
Definition
Meaning
The mean sea level as measured at Newlyn, Cornwall, used as the principal height reference for maps and surveys of Great Britain from 1915 to 2016.
A precise geodetic vertical datum, representing average sea level measured over a specific period, which served as the foundational zero-elevation point for all Ordnance Survey maps in the UK for over a century. It is now superseded by the Ordnance Survey National Grid.
Linguistics
Semantic Notes
This is a proper noun referring to a specific, historical geodetic standard. It is not a generic term for data or measurements. It is often used in historical or legacy contexts within surveying and mapping.
Dialectal Variation
British vs American Usage
Differences
The term is exclusively British in a technical context, referring to the national geodetic datum of Great Britain. In American English, the equivalent concept would be referenced by a different local datum (e.g., North American Vertical Datum of 1988 - NAVD88).
Connotations
In British English, it carries connotations of official mapping, precision, and historical continuity in land measurement. In American English, it would be recognized only by specialists familiar with international geodesy.
Frequency
Virtually never used in general American English. Its use in British English is confined to technical fields like surveying, civil engineering, and historical geography.
Vocabulary
Collocations
Grammar
Valency Patterns
The map heights are referenced to Newlyn Datum.The benchmark is 45.2 metres above Newlyn Datum.Newlyn Datum was established in 1915.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “Above/below Newlyn Datum”
Usage
Context Usage
Business
Almost never used. Might appear in highly specialized consultancy reports for land development or infrastructure projects with historical components.
Academic
Used in papers and textbooks on geodesy, cartographic history, physical geography, and surveying.
Everyday
Extremely rare. A person might encounter it on an old Ordnance Survey map legend or in a documentary about mapping.
Technical
Core term in surveying, civil engineering (for legacy data), and topographic mapping. Used when discussing historical survey data or converting old maps to modern coordinate systems.
Examples
By Part of Speech
adjective
British English
- Newlyn-datum-based measurements
- the historic Newlyn-datum benchmark
Examples
By CEFR Level
- This old map uses Newlyn Datum.
- The height of the hill is shown in metres above Newlyn Datum.
- Before converting the survey data, we must confirm whether it references Newlyn Datum or the newer OSGM15.
- The supersession of Newlyn Datum by the Ordnance Survey National Grid marked a significant shift from a tidal-based vertical datum to a gravimetric-geometric model.
Learning
Memory Aids
Mnemonic
Think of a NEW map LYING on a table, with all its heights measured from the NEWLYN Datum point at sea level.
Conceptual Metaphor
THE FOUNDATION OF MEASUREMENT (It is the foundational 'zero point' from which all vertical measurements on the land are built upwards).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not translate 'datum' as 'данные' (data). It is a technical singular noun meaning 'исходная точка', 'система отсчёта'.
- Avoid interpreting 'Newlyn' as a descriptive word; it is a proper place name.
- The phrase is a fixed technical term, not a descriptive combination of 'new' and 'something'.
Common Mistakes
- Pronouncing it as 'new-lynn' (it's 'new-lin').
- Treating 'datum' as plural (the plural is 'datums' in this technical sense, not 'data').
- Using it as a generic term for any sea level measurement.
Practice
Quiz
What does 'Newlyn Datum' specifically refer to?
FAQ
Frequently Asked Questions
No, it was officially replaced in 2016 by the Ordnance Survey National Grid (OSNG) as the primary vertical datum for Great Britain. However, historical maps and data will still reference it.
It is named after Newlyn, a fishing village in Cornwall, England, where the tidal measurements used to calculate the mean sea level were taken over a six-year period (1915-1921).
Mean sea level is an average measurement of the sea surface. A datum is a fixed, agreed-upon reference point or surface (based on such measurements) from which all other heights or depths are measured consistently on maps and surveys.
No. In technical surveying and geodesy, the plural of this type of 'datum' (a reference point) is 'datums'. 'Data' is the plural of 'datum' meaning a single piece of information.