Relation:building

Relations of type=building are used as one way to group elements that form a building in Simple 3D Buildings. Note that in many cases the added complexity of a relation is unnecessary--unless at least one part of a building is hanging over the building footprint, or the building has a complex structure with lots of parts, one can simply position building parts within a building outline as described in Simple 3D Buildings.

Disambiguation: This kind of relation modeling was also used for indoor mapping to group building levels, but with the introduction of Simple Indoor Mapping in 2012 these relations are deprecated. There was an earlier proposal for this tag in the context of address mapping, apparently abandoned in 2007.

Tagging

type=building are used in two contexts: 3D modelling and indoor mapping. We will here distinguish those two usages, however they can be combined in a same relation.

For 3D modelling

They relate building:part=yes, roof:ridge=yes and roof:edge=yes to a building outline.

Further details, in particular the properties that can be assigned to the individual parts of the building, are described in Simple_3D_Buildings.

Role	Elements	Recurrence	Comment
outline		one	The area that makes up the building outline. This outline must be tagged with building=*. The outline also holds any other tags (e.g. address, name, overall height, operator, ...) which apply to the building as a whole.
part		one or more	Building parts, tagged with building:part=*. These parts differ from each other in terms of height, roof-shape, colour, material, ...
ridge		zero or more	Ways which make up the roof ridges of a building or building part.
edge		zero or more	Ways which make up the roof edges of a building or building part.

For indoor mapping

There are different approaches for indoor mapping.

Simple Indoor Tagging

The Simple_Indoor_Tagging scheme does not need additional relations for the levels.

IndoorOSM

IndoorOSM is a deprecated tagging scheme that has been replaced by Simple Indoor Tagging.

An example of building relation (indoor mapping) and its members

The IndoorOSM proposal defines separate relations per level type=level and groups them into the building entity. Each level has a level_n role, where n is the level number (level_0 for ground). Entrances can be added in the relation with the entrance role. See also entrance=* and amenity=parking_entrance

Role	Elements	Recurrence	Comment
level_n		one or more	For type=level relations, with n as the level number (level_-1, level_0, level_1, ...). There should be at least one member (level_0).
entrance		one or more	Building entrances. There should be at least one member, the main entrance.

Examples

Examples tested 2023-07-29:

• Simple building with 3 members, the main house as the outline, two cylindrical parts on top, one of them defining the dome-shaped roof:
  • 3824021 3824021
  • 3D view: Frankfurter Tor, Berlin (osm2world)

• More complex church building with some towers and different roof types:
  • 3792630 3792630
  • 3D view: Niklolaikirche, Berlin (F4)

• Empire State Building
  • 2098969 2098969
  • 3D view: Empire State Building (F4)

• Indoor mapping example (with levels)
  • 3368293 3368293
  • 2D view: ECE Paris - Campus Eiffel, Paris (OpenLevelUp!)

Further Demo areas here.

See also

• ProposedRoofLines#Building Relation for proposals of further details.
• Simple 3D Buildings
• Key:building