Airy 1830 ellipsoid
E486592
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.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Airy 1830 ellipsoid canonical | 5 |
| Airy 1830 | 3 |
How this entity was disambiguated
This entity first appeared as the object of triple T5014794 — 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: Airy 1830 ellipsoid Context triple: [British National Grid, usesEllipsoid, Airy 1830 ellipsoid]
-
A.
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.
-
B.
Maclaurin spheroid
A Maclaurin spheroid is an oblate, rotationally symmetric ellipsoidal figure used in astrophysics and geophysics to model the equilibrium shape of a uniformly rotating, self-gravitating fluid body.
-
C.
Roche ellipsoid
A Roche ellipsoid is an equilibrium shape assumed by a self-gravitating fluid body that is tidally distorted by a nearby massive companion, important in the study of close binary systems and tidal interactions.
-
D.
Humboldt meridian
The Humboldt meridian is a principal survey meridian used as a reference line for land surveying and mapping in parts of northern California.
-
E.
Earth gravity model
The Earth gravity model is a mathematical representation of Earth's gravitational field used for precise positioning, navigation, and geodetic calculations.
- 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: Airy 1830 ellipsoid Target entity description: 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.
-
A.
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.
-
B.
Maclaurin spheroid
A Maclaurin spheroid is an oblate, rotationally symmetric ellipsoidal figure used in astrophysics and geophysics to model the equilibrium shape of a uniformly rotating, self-gravitating fluid body.
-
C.
Roche ellipsoid
A Roche ellipsoid is an equilibrium shape assumed by a self-gravitating fluid body that is tidally distorted by a nearby massive companion, important in the study of close binary systems and tidal interactions.
-
D.
Humboldt meridian
The Humboldt meridian is a principal survey meridian used as a reference line for land surveying and mapping in parts of northern California.
-
E.
Earth gravity model
The Earth gravity model is a mathematical representation of Earth's gravitational field used for precise positioning, navigation, and geodetic calculations.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
geodetic datum component
ⓘ
oblate spheroid ⓘ reference ellipsoid ⓘ |
| adoptedBy | Ordnance Survey ⓘ |
| authorityCode | EPSG:7001 ⓘ |
| axisUnit | metre ⓘ |
| basisOf |
British National Grid
ⓘ
OSGB36 datum ⓘ
linked to:
OSGB36
Ordnance Survey mapping in Great Britain ⓘ
linked to:
Ordnance Survey
|
| category |
cartography
ⓘ
geodesy ⓘ geodetic reference system ⓘ |
| comparedTo |
GRS80 ellipsoid
ⓘ
linked to:
GRS80
WGS84 ellipsoid ⓘ
linked to:
WGS84
|
| coordinateSystemType | ellipsoidal ⓘ |
| datumRealization | OSGB36 ⓘ |
| definedIn | 1830 ⓘ |
| designedToFit | geoid around Great Britain ⓘ |
| developedBy |
George Biddell Airy
ⓘ
linked to:
Sir George Airy
|
| flattening | 0.0033408506415 ⓘ |
| geodeticDatumType | local datum ellipsoid ⓘ |
| hasEccentricitySquared | 0.0066705397616 ⓘ |
| hasParameter |
flattening
ⓘ
semi-major axis ⓘ semi-minor axis ⓘ |
| historicalStatus | superseded for global positioning ⓘ |
| inverseFlattening | 299.3249646 ⓘ |
| namedAfter |
George Biddell Airy
ⓘ
linked to:
Sir George Airy
|
| optimizedFor | local fit to British Isles ⓘ |
| referenceSurfaceFor | British triangulation networks ⓘ |
| regionOfUse |
Great Britain
ⓘ
Ireland ⓘ |
| replacedInGlobalUseBy |
WGS84 ellipsoid
ⓘ
linked to:
WGS84
|
| semiMajorAxis | 6377563.396 metres ⓘ |
| semiMajorAxisShorterThan |
GRS80 ellipsoid
ⓘ
linked to:
GRS80
WGS84 ellipsoid ⓘ
linked to:
WGS84
|
| semiMinorAxis | 6356256.909 metres ⓘ |
| stillUsedFor |
legacy mapping products
ⓘ
national mapping in Great Britain ⓘ |
| usedFor |
geodetic calculations
ⓘ
mapping ⓘ surveying ⓘ |
| usedInCountry |
Ireland (historically)
ⓘ
linked to:
Ireland
United Kingdom ⓘ |
| usedInEpoch |
19th century
ⓘ
20th century ⓘ |
| usedWithCoordinateReferenceSystem | EPSG:27700 ⓘ |
| usedWithProjection | Transverse Mercator ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Airy 1830 ellipsoid Description of subject: 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.
Referenced by (8)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject linked to:
Ordnance Survey National Grid (approximate)
linked to: Airy 1830 ellipsoid
linked to: Airy 1830 ellipsoid
linked to: Airy 1830 ellipsoid