|man_made = survey_point|
|A triangulation pillar, geodetic vertex, or other piece of fixed equipment used by topographers.|
|Group: Man made|
|Used on these elements|
|Tools for this tag|
A survey point is a triangulation pillar, geodetic vertex, or other piece of fixed equipment used by topographers. These points are normally in a fixed location and of a known altitude used for old-fashioned surveying.
How to map
Add a node at the location of the trig point, tagged with man_made=survey_point.
It can be combined with the following generic tags: name=*, ele=*, ref=*, operator=*, description=*.
There are also three tags specific to survey markers: survey_point:structure=*, survey_point:datum_aligned=*, survey_point:purpose=*. See the tables below.
|survey_point:structure=beacon||A large structure, typically four-legged, visible from a far distance. Sometimes called a Trig Station.
Common in Australia and New Zealand.
|survey_point:structure=pole||A pole is much more slender and generally taller than a pillar.
In the photo, there are two poles. The shorter pole in the foreground is also a valid example of a pole
|survey_point:structure=pillar||Taller than it is wide, commonly designed for surveying equipment to be placed directly onto the top of the pillar.|
|survey_point:structure=block||A man-made block built into ground, with top of block often at ground level, or up to approximately 0.5m from ground level.|
|survey_point:structure=bracket||A plaque-like bracket that allows equipment to be hooked into it.
If you cannot hook equipment into it, then it is a plaque (see below)
|survey_point:structure=plaque||If there is only a plaque, and no other structure.
Use bracket (see above) if the plaque allows you to connect survey equipment.
|survey_point:structure=medallion||Circular plate embedded at the surface of a larger structure, typically a building. Survey instruments may be inserted in it for measures.|
|survey_point:structure=pin||If there is no physical structure, besides from the pin/bolt itself. See also: indented_pin
|survey_point:structure=indented_pin||Similar to pin, except that it has an indent for inserting survey equipment|
|survey_point:structure=cut||A line cut into a wall or rock|
|survey_point:structure=magnet||If the survey marker is an underground magnet. Please combine with location=underground||Example|
|survey_point:datum_aligned=yes||If the location of the marker is known to be reliably aligned to the nearest Geodetic datum.|
|survey_point:datum_aligned=no||If the location of the marker is NOT aligned to the local Geodetic datum.
This may be because of an earthquake/landslide/flood, or it was moved accidently, or moved by growing tree roots.
|survey_point:purpose=horizontal||Often called a Triangulation Point, this is used in geodetic surveys to measure horizontal distance between objects.|
|survey_point:purpose=vertical||Often called a Benchmark. Used to measure difference in elevation.|
|survey_point:purpose=both||If a marker can be used for both horizontal and vertical triangulation|
- If a survey marker has been destroyed, you may replace man_made=survey_point with destroyed:man_made=survey_point if you really want to map it, but keep in mind Good practice.
- If a survey marker still exists but is no longer visible, you could add location=underground. For marks embedded into the roadway, resealing the road may have covered the pin. Another example is if a building was constructed on top of the marker.
Survey points are currently not rendered in openstreetmap-carto.
suggested by User:Chrisana13