Also known as turning board, alhidade, alhidad, alidad
right|thumb|A simple alidade for use with a ceiling projector An alidade () (archaic forms include alhidade, alhidad, alidad) or a turning board is a device that allows one to sight a distant object and use the line of sight to perform a task. This task can be, for example, to triangulate a scale map on site using a plane table drawing of intersecting lines in the direction of the object from two or more points or to measure the angle and horizontal distance to the object from some reference point's polar measurement. Angles measured can be horizontal, vertical or in any chosen plane.
Wikidata facts
- Subclass of
- physical tool
- Image
- Alidade for ceiling projector.JPG
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- Commons category
- Alidades
Sources (1)
via Wikidata · CC0