[Tagging] man_made=mast for non communication uses?

Martin Koppenhoefer dieterdreist at gmail.com
Thu Feb 18 09:46:15 UTC 2016

2016-02-17 22:05 GMT+01:00 Marc Zoutendijk <marczoutendijk at mac.com>:

> Generally, when the definitions in OSM are different from what a person
> speaking the language might expect, it doesn't work. The issue here:
> "small" "a few meters high" seems not pertinent for radio masts which are
> among the tallest man made structures on earth, particularly when made of
> concrete or steel they can be hundreds of meters high. A quick image search
> confirms this (no small structures at all had been found)
> I was talking about a mast, not about towers.
> The wiki (how “unlucky" it may be) is clear on the difference between a
> mast and a tower. [1]

> [1] http://wiki.openstreetmap.org/wiki/Tag:man_made%3Dmast
> <http://wiki.openstreetmap.org/wiki/Tag:man_made=mast>

really, this is what I was writing about. You have asked, so here we go: it
does define some arbitrary rules that don't fit within the general meaning
of mast (as a mast can be very large, indeed the biggest masts are bigger
than the biggest towers) by saying they must be small. Then, it contradicts
itself by giving examples like this one:
(declaring it as a mast, and indicating the height as 40m +), and this one:
(although requiring "platforms" in the text this is given as an example for
a tower).
I do partly agree with the classification of the given examples, and I
believe the textual definitions are insufficient and partly "wrong"/not
well chosen, and the text contradicts the pictures.

There is also an inconsistency in that there now seems to be a
man_made=communications_tower as an alternative to the man_made=tower
tower:type=communication but the examples for tower and
communications_tower should be inverted (because the tower example is
clearly a pure communications tower, while the com tower example is clearly
a tower that has other purposes aside from the communication function it
also serves, e.g. it is a viewing platform (with a cafe that rotates inside
the sphere: takes roughly 30m for one turn) and had a clear political
message / representation function in 1970 when it was opened (going from
memory, figures could be slightly different).

Also there are tag suggestions I believe should be removed, e.g.
"communication:bos" which is a mash up of English and German (BOS=
Behörden, Ordnung, Sicherheit, a German  abbreviation for emergency radio).

Using tower:type on masts is a bit strange, but could be accepted (it is
simplifying the work of the data users).

man_made=communications_tower together with tower:type=communication seems
an odd recommendation, because it is clearly redundant.

Also I miss a statement on the mast page that the whole mast can be an
antenna itself (right now it is only stated that it can "hold" an antenna).
In osm there is also man_made=antenna and maybe this is the preferred tag
in this case, still something should be written about this on the mast page.

proposing "communication:microwave" for microwave_links seems to be
orthogonal to the intended type of communication (the German word
"Richtfunk" added there to the English version indeed describes links of
any wavelength and is not a translation of "microwave"). It is also odd in
this list of communication subtags (here without prefix):
(or are these communication features for microwave ovens?).

I don't think there is a reasonable system if we make a typological and
functional distinction for masts and towers but then introduce another
toplevel category  (man_made=communications_tower) for "Really big
communications towers >= 100 m". In this system, a tower with any height
but without any communication function would get the tower tag, like a
communication tower with a height of 99 m, but a tower with 101 m and some
antenna would get a completely different tag? How should I tag an office
tower with some antenna on top, communications tower if it's more than

Basically the mast page seems to be a collection of stuff people have put
there, without broader discussion I believe, because otherwise the
inconsistencies and contradictions of this page with other osm feature
definitions and pages would have come to light earlier.

> From a mast I'd expect to have guy wires, while a tower should typically
> be freestanding, so the word "small tower" doesn't seem to be a lucky
> choice either.
> I don’t expect guy wires, neither does the wiki, nor have I ever seen them
> in use for all (55 or so) man_made=mast structures that are in my
> neighbourhood (in the Nehterlands). Typically “small” masts of steel or
> concrete and about 5 - 15 meters high.

yes, you often won't have guy wires for structures between 5 and 15 meters
of height

> But that was not my question in the first place, I asked for the use of:
> man_made=mast
> mast=lighting
> or
> mast:type=lighting

I'm fine with this usage of mast. Or call it a "lighting_mast" right away,
no need to subtype (at least not at this functional level).
I also prefer the "mast:type" tag over the tower:type tag for a mast, and
it is already used in few numbers (including lighting value):

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