[Tagging] Feature Proposal - RFC - survey_point:benchmark

Greg Troxel gdt at lexort.com
Wed Mar 11 14:16:03 UTC 2020


"ITineris OSM" <itineris.osm at gmx.com> writes:

> I need help in tagging a special kind of survey points: geodesic towers.

Are they called "geodetic" towers?

> These are tubular concrete structures, with usual steel triangulation tripods on their top.

Wow, those are pretty big!

> They have the precise benchmark on the ground level, the tower is erected so that it's visible from far, being higher than the trees around.
> They form the base of the national reference grid.

I'm not sure if you mean "benchmark" as vertical control, or if you mean
the horizontal control mark and then the tower is basically over it, to
translate it up along the plumb line.


So the control point is man_made=survey_point.  Then there is a tower
which is physcially notable regardless, and the tourist bit.  OSM's
representation does not really admit multiple primary tags on objects,
except that sometimes they dno't conflict.

I'd put in man_made=survey_point as a node for the thing on the ground,
some survey_point:geodetic_tower=yes subtag on that (to inform those who
care about the survey aspect of that), maybe some kind of height tag,
and then draw a way around the tower and tag that as man_mde=tower
and/or tourism.

I don't think we should try to drag towerness and being an attraction
into the survey_point namespace; it seems easy enough to dneote multiple
properties separately.
[>


>  
>
> They could be tagging as <span style="color:#0000ff;"><span style="font-family:Courier New,Courier,monospace;">man_made=survey_point</span></span> because their main purpose is being a geodesic reference point.
>
> However, they could be a <span style="color:#0000ff;"><span style="font-family:Courier New,Courier,monospace;">man_made=tower</span></span>, for being a tower emerging from the surface - and to distinguish it from brackets, benchmarks or pavement rivets.
>
> Furthermore, additional functions can be connected to the latter only:
>
> Some of them are tourist attractions, like this https://hu.wikipedia.org/wiki/Cs%C3%B3v%C3%A1nyos#/media/F%C3%A1jl:Csovanyos2014_12.jpg. It is a <span style="color:#0000ff;"><span style="font-family:Courier New,Courier,monospace;">tower:type=observation</span></span>.
>
> If it's rigged with GSM and microwave antennae, it's <span style="color:#0000ff;"><span style="font-family:Courier New,Courier,monospace;">tower:type=communication</span></span>.
>
>
>  
>
> (And of course you may add the <span style="color: rgb(0,0,255);"><span style="font-family: Courier New , Courier , monospace;">triangulation_point=yes</span></span> tagging.)
>
>  
>
> So how would you tag them?
>
>  
>
> Greets,
> Ákos
>
>
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