Hayford 1909 ellipsoid
E1572541
UNEXPLORED
The Hayford 1909 ellipsoid is a historical reference ellipsoid of the Earth, widely used in early 20th-century geodesy and mapping, particularly in Europe and North America, before being superseded by more modern global models.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Hayford 1909 ellipsoid canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T23185765 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Hayford 1909 ellipsoid Context triple: [Bessel ellipsoid, comparedTo, Hayford 1909 ellipsoid]
-
A.
Airy 1830 ellipsoid
The Airy 1830 ellipsoid is a reference ellipsoid defined in the 19th century for geodetic calculations in Great Britain, forming the basis of traditional mapping systems such as the British National Grid.
-
B.
Bessel ellipsoid
The Bessel ellipsoid is a historical reference ellipsoid of the Earth defined in the 19th century for geodetic and cartographic purposes, particularly in Europe.
-
C.
GRS80
GRS80 is a geodetic reference ellipsoid defined in 1980 that serves as a standard mathematical model of the Earth's shape for modern mapping and surveying systems.
-
D.
Airy Modified ellipsoid
The Airy Modified ellipsoid is a slightly adjusted version of the Airy ellipsoid used as the reference surface for mapping and geodetic calculations in systems such as the Irish grid reference system.
-
E.
National Geodetic Vertical Datum of 1929
The National Geodetic Vertical Datum of 1929 is an older United States vertical reference system used to define elevations above sea level before being superseded by NAVD 88.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Hayford 1909 ellipsoid Target entity description: The Hayford 1909 ellipsoid is a historical reference ellipsoid of the Earth, widely used in early 20th-century geodesy and mapping, particularly in Europe and North America, before being superseded by more modern global models.
-
A.
Airy 1830 ellipsoid
The Airy 1830 ellipsoid is a reference ellipsoid defined in the 19th century for geodetic calculations in Great Britain, forming the basis of traditional mapping systems such as the British National Grid.
-
B.
Bessel ellipsoid
The Bessel ellipsoid is a historical reference ellipsoid of the Earth defined in the 19th century for geodetic and cartographic purposes, particularly in Europe.
-
C.
GRS80
GRS80 is a geodetic reference ellipsoid defined in 1980 that serves as a standard mathematical model of the Earth's shape for modern mapping and surveying systems.
-
D.
Airy Modified ellipsoid
The Airy Modified ellipsoid is a slightly adjusted version of the Airy ellipsoid used as the reference surface for mapping and geodetic calculations in systems such as the Irish grid reference system.
-
E.
National Geodetic Vertical Datum of 1929
The National Geodetic Vertical Datum of 1929 is an older United States vertical reference system used to define elevations above sea level before being superseded by NAVD 88.
- F. None of above. chosen
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.