Great Arc of the Meridian
E300812
The Great Arc of the Meridian was a monumental 19th-century geodetic survey line across the Indian subcontinent that played a key role in measuring the Earth’s shape and refining global maps.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Great Arc of the Meridian canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T2816609 — 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: Great Arc of the Meridian Context triple: [Great Trigonometrical Survey of India, notableWork, Great Arc of the Meridian]
-
A.
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.
-
B.
San Bernardino meridian
The San Bernardino meridian is a principal survey meridian used as a reference line for land surveying and mapping in Southern California and parts of Nevada.
-
C.
Polar Circle
Polar Circle is a cold-climate wildlife exhibit at the Central Park Zoo featuring Arctic species such as penguins and polar bears in a simulated polar environment.
-
D.
Tropic of Capricorn
The Tropic of Capricorn is the southernmost latitude where the sun can appear directly overhead, marking an important boundary of the Earth's tropical zone.
-
E.
Tropic of Cancer
The Tropic of Cancer is the northernmost latitude on Earth where the sun can appear directly overhead, marking the boundary of the tropical zone in the Northern Hemisphere.
- 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: Great Arc of the Meridian Target entity description: The Great Arc of the Meridian was a monumental 19th-century geodetic survey line across the Indian subcontinent that played a key role in measuring the Earth’s shape and refining global maps.
-
A.
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.
-
B.
San Bernardino meridian
The San Bernardino meridian is a principal survey meridian used as a reference line for land surveying and mapping in Southern California and parts of Nevada.
-
C.
Polar Circle
Polar Circle is a cold-climate wildlife exhibit at the Central Park Zoo featuring Arctic species such as penguins and polar bears in a simulated polar environment.
-
D.
Tropic of Capricorn
The Tropic of Capricorn is the southernmost latitude where the sun can appear directly overhead, marking an important boundary of the Earth's tropical zone.
-
E.
Tropic of Cancer
The Tropic of Cancer is the northernmost latitude on Earth where the sun can appear directly overhead, marking the boundary of the tropical zone in the Northern Hemisphere.
- F. None of above. chosen
Statements (46)
| Predicate | Object |
|---|---|
| instanceOf |
geodetic survey
ⓘ
meridian arc ⓘ |
| associatedWith |
Andrew Scott Waugh
ⓘ
George Everest ⓘ William Lambton ⓘ |
| challenge |
difficult terrain and climate
ⓘ
need for extremely precise angle measurements ⓘ |
| continent | Asia ⓘ |
| country | British India ⓘ |
| direction | north–south ⓘ |
| endPoint |
Banog
ⓘ
near Mussoorie ⓘ |
| hasField |
cartography
ⓘ
geodesy ⓘ surveying ⓘ |
| heritageStatus | considered a landmark achievement in the history of surveying ⓘ |
| historicalSignificance |
foundation for later topographic mapping of South Asia
ⓘ
major contribution to 19th-century geodesy ⓘ one of the longest meridian arcs ever measured ⓘ |
| influenced |
global geodetic reference values
ⓘ
subsequent national surveys in Asia ⓘ |
| length | approximately 2,400 kilometres ⓘ |
| locatedIn |
Indian subcontinent
ⓘ
linked to:
South Asia
|
| operator | Survey of India ⓘ |
| partOf | Great Trigonometrical Survey of India ⓘ |
| passesThrough |
Central India
ⓘ
Himalayan foothills ⓘ Madras Presidency ⓘ |
| purpose |
determination of Earth’s shape
ⓘ
establishment of accurate geodetic control in India ⓘ measurement of Earth’s curvature ⓘ refinement of global maps ⓘ |
| result |
high-precision mapping of India
ⓘ
improved value for Earth’s radius ⓘ refined value for Earth’s flattening ⓘ |
| risk | high mortality among survey teams ⓘ |
| significantWorkPeriod |
early 19th century
ⓘ
mid 19th century ⓘ |
| startDate | 1802 ⓘ |
| startPoint |
Cape Comorin
ⓘ
linked to:
Kanyakumari
Kanyakumari ⓘ |
| usesInstrument |
baseline measuring apparatus
ⓘ
theodolite ⓘ zenith sector ⓘ |
| usesMethod |
meridian arc measurement
ⓘ
triangulation ⓘ |
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: Great Arc of the Meridian Description of subject: The Great Arc of the Meridian was a monumental 19th-century geodetic survey line across the Indian subcontinent that played a key role in measuring the Earth’s shape and refining global maps.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.