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#1 2013-09-17 00:47:25

things-change
Member
Registered: 2011-10-27
Posts: 351

Roof Modelling

Hy there,

I've got a problem with modelling some kind of roofs. How would you tag this roof?:

http://goo.gl/maps/OvVC3

(The left one, for the case that the focus isn't perfectly)

Normally it is roof:shape=gabled, but with the shorter part in the north it won't work. I also tried to work with roof ridge/edge, but i don't get the right roof.

Does anyone know how to tag this?

Thanks for your help.

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#2 2013-09-17 08:00:29

cmif4
Member
From: Paris
Registered: 2013-06-10
Posts: 121
Website

Re: Roof Modelling

Hi,

if you want the perfectly right rendering for F4map (even it is forbidden to tag for a specific renderer) you should split your building in 2 parts.

For now our roof algorithm is very naive and adapt the ridge to the minimal oriented bounding box.

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#3 2013-09-17 08:15:44

!i!
Member
Registered: 2009-11-28
Posts: 3,313
Website

Re: Roof Modelling

Basicly I would do a similar approach. Not sure, maybe O2W and Kendzi 3D can figure out the right shape by just using a roof:shape=gabled on the single building outline.


privater Account von KVLA-HRO-Mei

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#4 2013-09-17 13:01:58

things-change
Member
Registered: 2011-10-27
Posts: 351

Re: Roof Modelling

I don't know how this could work with to parts. I also tried this. The Problem is, that the shorter ridge is not at the highest point. it has no defined height. If I draw a second part there, I don't know the height and there would be a step.
I think, with the actual Tags it is not possible to tag this roof. If anyone knows, how this could be tagged, please tell me.
It's a big problem for me, in this area many roofs have this shape.

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#5 2013-09-17 20:05:15

kendzi
Member
Registered: 2008-08-20
Posts: 250

Re: Roof Modelling

!i! wrote:

Not sure, maybe O2W and Kendzi 3D can figure out the right shape by just using a roof:shape=gabled on the single building outline.

I don't known algorithm with could handle this case.

things-change wrote:

I don't know how this could work with to parts.

Personally I thing that gabled shape is good approximation of this roof. But if you want to do it more precisely you need to split it into parts, which involve adding heights.

x8c5.png

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#6 2013-09-22 18:33:00

things-change
Member
Registered: 2011-10-27
Posts: 351

Re: Roof Modelling

I think, there have to be additional Tags/additional rendering because actually some roofs couldn't be build in OSM.

If the beginning of a roof is not all around at the same height, you'll get wrong renderings.
Even the roof I meant in #1 is actually not to draw in OSM.
There have to be solutions for this kind of roofs.
I don't know how this could work.

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#7 2013-10-18 23:17:16

marek kleciak
Member
Registered: 2010-10-11
Posts: 8,439

Re: Roof Modelling

If I draw a second part there, I don't know the height and there would be a step.
I think, with the actual Tags it is not possible to tag this roof. If anyone knows, how this could be tagged, please tell me.
It's a big problem for me, in this area many roofs have this shape.

Things-change, let´s talk about it. Do You have contact data of me?

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#8 2013-10-20 21:23:57

marek kleciak
Member
Registered: 2010-10-11
Posts: 8,439

Re: Roof Modelling

cmif4,

Please change rendering rules for roof:shape=round.
If bounding box longer  than12 m then resolution= 24 -effective for the half cirlce=12
If the bounding box longer than 20m then resolution= 32 -effective for the half cirlce=16
If the bounding box longer than 32 m then resolution= 48 -effective for the half cirlce=24

or something like this...


See http://www.openstreetmap.org/#map=19/53.02847/18.65280

We need support of half_dome. I suggest the use of half cirlce in the top view with the attribute roof:shape=half_dome and automatic calculation of the hight from the half circle diameter.

Regards,
Marek

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#9 2013-10-20 21:26:38

kendzi
Member
Registered: 2008-08-20
Posts: 250

Re: Roof Modelling

Could you make some images how half_dome could look like?

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#10 2013-10-20 21:39:09

marek kleciak
Member
Registered: 2010-10-11
Posts: 8,439

Re: Roof Modelling

OK. Maybe short description in assembler:
" Cwiartka jablka. Przecinam jablko horyzontalnie, wywalam dolna polowe. Sprytnym ciosem noza po pionie odkrajam jedna czwarta. Dostaje to, jak np wyglada muszla koncertowa filharmonii w operze lesnej przy pomocy tagu depth=value opisujace grubosc konstrukcji  robie z tego wneke "
Example:
http://images29.fotosik.pl/267/837802be6f3d96f6.jpg

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#11 2013-10-22 07:39:57

things-change
Member
Registered: 2011-10-27
Posts: 351

Re: Roof Modelling

marek kleciak wrote:

If I draw a second part there, I don't know the height and there would be a step.
I think, with the actual Tags it is not possible to tag this roof. If anyone knows, how this could be tagged, please tell me.
It's a big problem for me, in this area many roofs have this shape.

Things-change, let´s talk about it. Do You have contact data of me?

Du hast eine PN

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#12 2013-11-04 22:21:03

marek kleciak
Member
Registered: 2010-10-11
Posts: 8,439

Re: Roof Modelling

I see more and more the need of implementation of roof type "3.4." from http://wiki.openstreetmap.org/wiki/OSM-4D/Roof_table .

The difference is only - I describe there rectangular shape, but it should work for every possible geometry of building outline.
I think it´s not so complicated to implement it.

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#13 2013-11-04 23:49:07

j3d
Member
Registered: 2013-05-07
Posts: 53

Re: Roof Modelling

If we could keep it simple and use a constant offset to the outline then it should be easy to implement and also work for non-rectangle outlines. What about quadruple_saltbox with only parameter roof:ridge:offset with default offset being roof:height?

In jts/geos this could be implemented with buffer operation and join type mitre. As segments may collapse with this operation (in general) one could get the start of the roof by positive buffering the result by the same amount.

roof_buffer.png

green is the original, blue is flat area and purple is slope area

Edit: of course the offset could also be determined from roof:height together with roof:angle

Last edited by j3d (2013-11-05 03:46:33)

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#14 2013-11-05 01:00:21

j3d
Member
Registered: 2013-05-07
Posts: 53

Re: Roof Modelling

I wasn't so far off with the above estimation for what kind of outlines will be tagged quadruple_saltbox :)

http://opensciencemap.org/~jeff/test/#s … ,lon=8.831

Last edited by j3d (2013-11-05 01:02:33)

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#15 2013-11-05 08:24:09

marek kleciak
Member
Registered: 2010-10-11
Posts: 8,439

Re: Roof Modelling

j3d,

Very good job! I agree fully.
I would say, we can extend now the simple 3d definition with this roof type.
Any voices against this idea?

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#16 2013-11-05 22:41:22

kendzi
Member
Registered: 2008-08-20
Posts: 250

Re: Roof Modelling

But how we would like to name it?

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#17 2013-11-06 03:51:31

j3d
Member
Registered: 2013-05-07
Posts: 53

Re: Roof Modelling

Just 'saltbox', 'flat_mansard' or 'mansard' with additional parameter? I think this is also related to the 'frustum' suggestion on s3db talk page.

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#18 2013-11-06 12:06:47

marek kleciak
Member
Registered: 2010-10-11
Posts: 8,439

Re: Roof Modelling

Flat mansard sounds great smile
Could You add it to the s3d specification?

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#19 2013-11-10 15:15:45

things-change
Member
Registered: 2011-10-27
Posts: 351

Re: Roof Modelling

How can I reach that square roofs are rendered in the right direction (across/along)?

Here f4map turns the roof in the middle, osm2world Map turns the right one:

http://map.f4-group.com/#lat=52.2213128 … hi=-33.346

http://maps.osm2world.org/?zoom=18&lat= … ers=B0TTFF

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#20 2013-11-11 06:39:14

kendzi
Member
Registered: 2008-08-20
Posts: 250

Re: Roof Modelling

That buildings are almost square so you should not use roof:orientation tag. That tag it won't work on square like buildings. You could try to roof:direction but i don't known if F4 is support it.

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#21 2013-11-11 14:37:52

marek kleciak
Member
Registered: 2010-10-11
Posts: 8,439

Re: Roof Modelling

Somthing goes wrong with the new implementatin:
Look here:
http://map.f4-group.com/#lat=49.5463139 … hi=-42.399

http://www.openstreetmap.org/browse/way/245633207
Roof is there simply - gabled...

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#22 2013-11-13 07:05:16

things-change
Member
Registered: 2011-10-27
Posts: 351

Re: Roof Modelling

kendzi wrote:

That buildings are almost square so you should not use roof:orientation tag. That tag it won't work on square like buildings. You could try to roof:direction but i don't known if F4 is support it.

cmif4 said in another topic that they use roof:orientation.
But when there is a problem with square buildings, we should have a tag to define it right.
f4map also handles  roof:slope:direction=float, but they don't let the direction snap on a side. Imho that is not good. And I don't know, if any other map handles this tag.

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