[Tagging] tower types, cooling towers etc.

"Christian Müller" cmue81 at gmx.de
Fri Nov 10 04:44:09 UTC 2017

On Thu, Nov 9, 2017 at 4:35 PM, Martin Koppenhoefer <dieterdreist at gmail.com> wrote:
> I just noticed that the tagman_made=cooling_tower is deprecated.
> The template says the reason is on the deprecated features list, but actually there is no reasoning there.

+1.  People are moving forward too fast without documenting their intermediate steps, leaving no space for proper result checking, or proper reasoning from a third party.  This opens a gate for errors.

That said, I do not oppose the effort around classifying /man_made/ towers with the tower:type tag in general.  E.g. have a look at [1].  It summons different tower types just as tower:type does, but maybe not to the same extent.

> There are also other values for tower:type that contradict the man_made=tower definition.

This should be fixed, either way is possible, adjusting the def. or the values.

According to [1] there are clear definitions to differentiate towers from masts.
These defintions vary with the ones used in OSM wiki, however.

But [1] is not the holy grail either.  E.g. it tries to
distinguish towers from buildings by assuming that all
buildings must be habitable.  This is a dead end imho:
- there are habitable towers (e.g. eiffel tower had/has an apartment)
- towers are (informally) a subclass of buildings if other defs apply, see [2]
- towers, bridges and buildings are man_made /structures/,
if a /structure/ is defined as the result of building activity by man

Last bulletin is /not/ a pledge to introduce man_made=structure structure=(tower, bridge, house, ..) however.  It seems most if not all objects tagged with man_made are structures (?).  Hence /structure/ value would not serve well the purpose of a value: to discriminate objects into classes.  It is rather synonym to /man_made/, the key itself or how it is used within OSM.

The key /man_made/ should be stressed, i.e. natural towers should not be tagged using man_made=tower.


[1] https://en.wikipedia.org/wiki/Tower
[2] https://en.wikipedia.org/wiki/Building#Definitions

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