| +/- man_made=survey_point
Triangulation pillars, geodetic vertices, and fixed equipment used by topographers (e.g. DGPS radio stations).
These points are normally in a fixed location and of a known altitude used for the old fashioned trigonometry and cartography.
See also wikipedia:Triangulation station
How to map
suggested by User:Chrisana13
- aerial=yes for extra markings meant to be visible in aerial photographs - a white cross, usually
- In the UK tpuk_ref= can be used for the ID of a trig point on the trigpointinguk.com website.
Related terms: <survey point>