Triangulation point symbol

A small triangle with a central dot, marking a surveyed height and position.

Also known as: Trig point, Trig pillar, Triangle with a dot

Maps & navigationStandard profile

Meanings

A triangle with a dot marks a triangulation station — a point whose position and height were surveyed precisely. The pillars they mark are largely obsolete for surveying and remain as landmarks.

Officially standardisedVerified fact
Marks a triangulation station whose position and height were established by survey, with the height printed beside it.
United Kingdom · Contexts: Navigation, Maps
Historically documentedVerified fact
Marks a network built for triangulation survey, a method largely superseded by satellite positioning — so most of the pillars now serve as landmarks rather than instruments.
Contexts: History, Navigation, Maps

Visual description

A small equilateral triangle standing on its base with a single dot at its centre, drawn in blue or black on the map.

Symmetry: vertical
Orientation: upright
Colours: blue, black

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is defined by a current official standard.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references.

Sources

Ordnance Survey map symbols and legends
Ordnance Survey · retrieved 2026-08-01
The national mapping agency's own published legend. Authoritative for British Ordnance Survey mapping and for nothing else — the same drawing may carry a different meaning on another country's maps, and every record citing this states its jurisdiction.
Triangulation station
Wikipedia · retrieved 2026-08-01
Tertiary reference. Used for what a symbol depicts and which authority publishes it, not for the legend of any particular chart series or the text of any standard.

Last reviewed 2026-08-01

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Map, chart and weather symbols

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Meanings

A triangle with a dot marks a triangulation station — a point whose position and height were surveyed precisely. The pillars they mark are largely obsolete for surveying and remain as landmarks.

Officially standardisedVerified fact

Marks a triangulation station whose position and height were established by survey, with the height printed beside it.

United Kingdom · Contexts: Navigation, Maps

Historically documentedVerified fact

Marks a network built for triangulation survey, a method largely superseded by satellite positioning — so most of the pillars now serve as landmarks rather than instruments.

Contexts: History, Navigation, Maps

Confidence

IdentityHigh confidence: High confidence because the identity is defined by a current official standard.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is defined by a current official standard.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references.

Sources

Ordnance Survey map symbols and legends
Ordnance Survey · retrieved 2026-08-01
The national mapping agency's own published legend. Authoritative for British Ordnance Survey mapping and for nothing else — the same drawing may carry a different meaning on another country's maps, and every record citing this states its jurisdiction.
Triangulation station
Wikipedia · retrieved 2026-08-01
Tertiary reference. Used for what a symbol depicts and which authority publishes it, not for the legend of any particular chart series or the text of any standard.

Last reviewed 2026-08-01