[OSM-talk] Door to door routing to buildings with multiple occupants

[Martin Koppenhoefer]

2012/11/29 Rob Nickerson <rob.j.nickerson at gmail.com>:
> Where should amenity=* and addr:*=* be tagged? One suggestion was to add all
> the detail to the entrance node, but this seems odd to me. For single
> occupancy buildings I suggested tagging the building as amenity=*, etc as
> the entrance node on the building can be easily matched with these.


it is better to distinguish the building from the occupancy to avoid
confusions to which entity the tags belong. There can be ambiguity
e.g. in name, operator, start_date, description, wikipedia, and
others. You can overcome this by splitting them into logic entities.

If you say that the building is a polygon (or mp relation), we get
basically these options for the "shop":
1a) a node for the shop floating inside the building
1b) like 1a but part of the outline
2a) a multipolygon with the building as outer
2b) an explicit polygon overlapping with the building
3) a relation that somehow says what is in this building

current consense seems to be 1a) 2a) and 2b) but some people also do 1b)

1b) has the disadvantage that the shop is inside the building but with
this way of mapping it is in between outdoors and inside.

a shop has always some extent, so I'd consider 1a) preliminary (it
would be better to have the area to see how big it is etc.)

2a) doesn't duplicate geometry but it might break often (due to
missing editor support in some editors)

2b) creates redundant geometry (overlapping way)

3) either doesn't tell you much about the extent or it will be very
similar to 2a,  and their might be other problems as well (e.g. also
missing editor support at the moment)


> But what about a building with multiple occupants and entrances. For example
> 2 shops in one building.


entrances can be mapped with the key "entrance"
http://wiki.openstreetmap.org/wiki/Key:entrance


> One option is to tag the building with building=yes
> and then add the amenity tags to individual nodes, but then how would door
> to door routing work?


first you'd need to make sure the doors are mapped ;-)


> An alternative is to just split the building in to 2
> areas (but technically its 1 building). Can we use some form of indoor
> mapping (e.g. room=yes, amenity=*)?


there is building:part (for parts of a building obviously), but also
with one big building there is no problem with putting several
amenity-polygons inside. If there is 1 building in the real world we
should also have one object in OSM which says "this is one building"
(i.e. a polygon or multipolygon with building=*), so bascially you
would need 3 polygons to map a building with 2 POIs in it.

You don't need a room-concept to map the extent of a POI, but there is one ;-)
http://wiki.openstreetmap.org/wiki/Proposed_features/indoor

cheers,
Martin