# leaning towers

I’m thinking about special tags for leaning towers

http://en.wikipedia.org/wiki/List_of_leaning_towers

tagging could be :

leaning:tilt : in degrees (default) or meters
leaning:azimuth : in degrees from north, or simply an orientation (NW, SSE)

leaning=shearing when the tilt maintain horizontal plane

some examples :

there are some building with both leaning but i’m not yet sure how to handle those, ideas are welcome !

What do you think ?

That’s an interesting topic, and I’ve been thinking about similar (but slightly different) cases recently. Specifically, there is often the situation that some faces of a building, rather than the entire building, are inclined. From my (limited) personal experience, I would even consider such per-face inclines more common than an entire leaning tower.

Therefore, I’m wondering if we can find an approach that covers both cases.

Per-face inclines can be covered with leaning building:parts I think

What’s about tagging the opposite of an roof.
It could be tagged similar to
“roof:shape=skillion” as
“bottom:shape=skillion”.
This tower could be tagged with three vertical “building:parts”.

It would also be helpful for other shapes like “round” or “dome” (http://de.wikipedia.org/wiki/Atomium) or one-sided leaning.

Edit:
If we find a solution, maybe I would create this: http://de.wikipedia.org/wiki/Jefferson_National_Expansion_Memorial

yep per face incline would be nice, for building like :

| /
\ |
| |

but it’s quite hard to define which face is leaning

it can indeed be done using building:parts but it’s quite hard to get right, and it’s more of a workaround than a solution

An other idea:
“building:axis=x;y”
Pre defined is the start point 0;0 on ground or bottom of building:part (height=0 or min_height=z[ground]). The coordinate x;y plus building:height (as z[top]) defines the axis as line.
It also works with pyramidal shapes or asymmetric gabled roofs (roof:axis=x;y) (https://www.schwoererhaus.de/de/haeuser/searchhouse/166)

Indeed: building:part is a workaround, but we talk about Simple 3D. Simple is: less rules and less basic types

You do not need: leaning=shearing
If the roof is horizontal than you can use roof:shape flat, else use roof:shape=skillion…

axis looks really hard to get, using an additional point as axis may be more user friendly imho
however a point as axis won’t help for roofs on complex forms.

if you have a tower with a flat roof, but the whole tower is leaning, if you can’t specify shearing, you won’t be able to map it.

maybe also include a way to indicate a part is bigger at the top than at the bottom on all sides
(like the top of chichen itza : http://demo.f4map.com/#lat=20.6831797&lon=-88.5687217&zoom=21&camera.theta=61.665&camera.phi=35.809 )

for example :
leaning=funnel
leaning:tilt=1m

we may even be able to use this with an angle to indicate a side of the building is leaning, what do you think ? (not very straightforward though)

I have another idea that might be useful. But I need to describe some context first:

To tackle the problem that sometimes part of a building’s walls can have a different colour, material etc. than the rest, I’ve thought about proposing a building:wall=yes tag. It would allow you to draw a way on a part of the building outline and add tags like building:colour etc. to it.

It’s loosely based on an idea I discussed with Kendzi in the past. The idea was well received in the German community. I’ve also created a quick test how this could be implemented in OSM2World, perhaps this clarifies what I’m talking about:

So what does that have to do with leaning towers? I was thinking that, maybe, we could add angles to the building wall ways. This would allow different leanings per wall, plus buildings that get wider or narrower towards the top.

looks easy to use

looks like someone is already using building:wall=yes

https://getsatisfaction.com/f4map/topics/building-walls-with-different-colors