Add rendering for man_made=tower

[NonnEmilia]

Actually man_made=tower is not rendered, but if building=* tag is present yes.
Taginfo said that only 8% have also building=* cause, according to the wiki, building=* tag on man_made=tower is not needed.

Should man_made=tower be renderd as buildings?

[dieterdreist]

actually only a small amount of all towers are mapped as outline, so it is
not possible to render them the same way we render buildings. Also the tag
is used for very different kinds of towers, so I'd prefer to render
specific "tower:type"s and not all kinds of towers with an icon (especially
on lower zooms). Anyway, a tower is also a building so I don't want to
discourage adding a building tag to tower polygons neither.

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[tyrasd]

Interestingly, man_made=mast is rendered with its own icon, although that tag is much less frequently used in comparison with man_made=tower:

[dieterdreist]

2013/9/20 Martin Raifer [email protected]

Interestingly, man_made=mast is rendered with its own icon, although that
tag is much less frequently used in comparison with man_made=tower:

yes, but it is more clear what that is, and they tend to be all landmarks,
what can't be said for all towers...

[jaakkoh]

@tyrasd / @dieterdreist : I haven't dug into what triggers the above rendering and e.g. Taginfo doesn't show usage combinations so I won't guess. But I do know that at least if there's a tower:type=communication in conjunction with man_made=mast then that icon is shown in OSM Mapnik (example: http://www.openstreetmap.org/node/2666366790).

I think this same rendering should happen when using man_made=tower (with tower:type=communication), which currently doesn't (http://www.openstreetmap.org/node/2489765793).

I opened a separate issue for (always) rendering tower:type=communication - #339 .

[matthijsmelissen]

See also https://trac.openstreetmap.org/ticket/1642

[matkoniecz]

Towers that are also buildings should be tagged also with building tag (what will render them). Other towers are special, it is impossible to show all using one method and maybe some should not be rendered. Probably tower:type may be used (available in the database) - see #339.