[Tagging] mast / tower / communication_tower (again)

SelfishSeahorse selfishseahorse at gmail.com
Sat Sep 29 14:53:08 UTC 2018


On Sat, 29 Sep 2018 at 00:29, Michael Booth <boothym at gmail.com> wrote:
> The Wiki definition is: "a huge tower for transmitting radio applications.... It is often made from concrete and usually a far visible landmark." https://wiki.openstreetmap.org/wiki/Tag:man%20made=communications%20tower
> Looking at examples of this tag in OSM I would guess that out of the <4,000 objects worldwide most of them do not conform to that definition. Many of them are small mobile phone/cell site "masts", towers less than 100m, or very tall guyed masts.

I fail to understand the difference between a
man_made=communications_tower and man_made=tower +
tower:type=communication. Aren't all towers far visible landmarks?
When is a tower huge? The wiki page also says that 'another indication
is, that a man_made=communications_tower has stairs and a lift inside,
whereas as man_made=tower, tower:type=communication has to be climbed
on the outside.' However this is contradictory with the definition of
man_made=tower: 'a tower is accessible and provides platforms, whereas
a mast only offers ladder steps to climb it.'

It might be better to discourage man_made=communications_tower and tag
them man_made=tower + tower:type=communication + height=*.

> I'd like to retag the structures near me to something more suitable - however the wiki pages aren't very clear in distinguishing between the various constructions and sizes for masts and towers.

I'm not an expert on this, but i think the distinction steps/lift
inside (= tower) vs latter outside (= mast) makes sense.

> Hopefully people can agree that the following should be tagged as man_made=mast or tower + tower:type=communication + tower:construction + height? Using TV transmitters in the UK as examples:
> * mast - guyed lattice, 306m: https://en.wikipedia.org/wiki/Durris_transmitting_station
> * mast - guyed tube, 351m: https://en.wikipedia.org/wiki/Belmont_transmitting_station
> * tower - lattice, 219m: https://en.wikipedia.org/wiki/Crystal_Palace_transmitting_station
> * tower - freestanding, 330m: https://en.wikipedia.org/wiki/Emley_Moor_transmitting_station

I would have tagged them the same.

> But how should these examples be tagged in OSM? All of them are self-supporting structures, so in engineering terms they are not masts.
> 1. https://binged.it/2xILZO9
> 2. https://www.geograph.org.uk/photo/2361955
> 3. https://www.geograph.org.uk/photo/2337468
> 4. https://en.wikipedia.org/wiki/Charwelton_BT_Tower
> 5. https://www.geograph.org.uk/photo/2053885
> 6. https://binged.it/2xTxcQK
> 7. https://fr.wikipedia.org/wiki/Tour_hertzienne_de_Villeneuve-d%27Ascq
> 8. https://www.geograph.org.uk/photo/2162874

Why aren't 2, 3, 5, 6 and 8 masts and 4 and 7 towers? Because the
structure itself is an antenna?

By the way, i'm wondering if poles with mounted antennas like in the
following image can also be called masts or if man_made=pole
(undocumented, but 2 047 uses so far) would be better?



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