[Tagging] Additional sub tags for survey mark

Philip Barnes phil at trigpoint.me.uk
Thu Nov 23 15:06:37 UTC 2017



On 23 November 2017 14:37:53 GMT+00:00, Craig Wallace <craigw84+osm at gmail.com> wrote:
>On 2017-11-20 23:47, Warin wrote:
>> Hi,
>>
>> There have been attempts in the past to add sub tags to
>> man_made=survey_point
>> https://wiki.openstreetmap.org/wiki/Tag:man_made%3Dsurvey_point
>>
>> To me there are 2 'types'. they are quite different;
>>
>> Triangulation (or 'trig point') that are visible over quite some
>distance (say over 2 km),
>> used to triangulate a position without having to go to the mark.
>Usually a pole standing on top of a rise/hill.
>>
>> Benchmarks that are visible on the surface but cannot be sighted at
>any distance. They can be small brass plaques fastened to the ground or
>engraved into stone.
>> These are used by surveyors by placing a tripod over the mark, thus
>have to be locally approached.
>>
>> If consideration is given to
>https://wiki.openstreetmap.org/wiki/Seamarks/Categories_of_Objects#Control_Points_.28CATCTR.29
>>
>> then expanding survey_point in a similar manner could be
>>
>> survey_point:configuration=triangulation/benchmark
>>
>> I use 'configuration' rather then 'type' or 'category' as it is more
>specific as to what is meant.
>>
>> Any thoughts?
>> Are there any other configurations?
>It would be useful to tag the physical style of the survey point. ie
>the 
>size and shape and what it  is made of. Is it a pillar, or just a metal
>
>plate or bolt on the ground. This would tell you whether it is an 
>obvious landmark or not.
>
>Tagging what the survey point is used for is a separate thing. ie 
>triangulation, or a benchmark. Nowadays most trig points are redundant,
>
>so they are not actually used for any sort of survey work. Though in
>the 
>UK there are some still maintained as "passive stations", plus a few 
>"active stations" (with a GPS receiver).
>Note there are some "Fundamental Benchmarks", which are a small stone 
>pillar.
>
>Some of the common types in the UK: http://trigpointing.uk/wiki/Types
>

Trig points are an important feature in UK outdoor circles, particularly in mountain and moorland areas. They are places you head to and obviously give a precise reference as to where you are. 

Some have been adopted by groups who maintain them for future generations.

They also provide a good place to sit and watch the world below, my OSM username is no accident. 

Phil (trigpoint) 


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