[OSM-talk] [Spam?]Re: [Spam?]Re: Underground / hovering buildings

David Murn davey at incanberra.com.au
Fri Feb 18 12:17:02 GMT 2011


On Fri, 2011-02-18 at 11:16 +0100, M∡rtin Koppenhoefer wrote:
> 2011/2/18 David Murn <davey at incanberra.com.au>:
> > Because the use of (min_)levels,height is in use by 3D renderers and
> 
> 
> IMHO this min_level-part of the advanced building proposal is not
> working (is using wrong semantics), at least for the illustration you
> can find in the wiki. building_levels should be the amount of building
> levels. If a building forms a "bridge" like in the illustration, where
> adjacent buildings have 7 levels, the "bridge" has only 2 levels and
> the 5 levels below are void, the proposal states you should still
> apply building_levels=7 and count the voids as levels.
> 
> This is against any common practise and definition in architecture,
> building law and the definition of building_levels in the wiki.

The wiki page this was taken from, is
http://wiki.openstreetmap.org/wiki/OSM-3D#Buildings

The relevant section (for building:min_level) states:

---
Explanation of building height tags
For parts of building that are "floating in air" (actually, they are
supported by other building parts that are fixed into ground), number of
floors from ground that are not present. So if there is a passage under
building, where 5 floors are missing, use building:min_level=5 

Note that building:levels still counts floors from the ground, including
also those nonexistent "skipped" floors, as can be seen in the
explanatory picture

number of levels is multiplied by 3 m to estimate the actual height
---

So while it may not meet any building law or such, its use in this
instance is simply as a rough guide instead of inputting an exact
building height.

David




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