Hello, I am fairly new to OSM. Sometimes, I see "address" points on top of buildings. Should I merge the two, or leave them separate? Thanks!

asked 28 Mar, 16:32

Mappingbananas's gravatar image

accept rate: 0%

This is a valid way of mapping addresses, and tools that use addresses should allow for it. So in general, I would not spend time changing this. Perhaps an exception would be if there is a very well-established practice in the local area of mapping addresses on building polygons, and I could see some real advantage to making the change.

I may be influenced by my local area where addresses are normally mapped on nodes (usually at or near the entrance), so if I were to make a change like this, I would be interfering with established practice.

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answered 28 Mar, 17:25

alan_gr's gravatar image

accept rate: 15%

Thanks for the quick response (and advice) !

(28 Mar, 22:47) Mappingbananas

As alan_gr mentioned, an address node inside a building's perimeter is an accepted mapping technique. It's not an error that needs to be fixed.

Adding the address tags directly to the building is also an accepted mapping technique, and might be preferable in some situations. The obvious advantages are 1) it's one database object instead of two, and 2) it's easier for software to find the address of the building by just examining the building's tags, instead of scanning for nodes inside the building and checking their tags.

There are definitely situations where a mapper might choose to use address nodes rather than address tags directly on the building -- a building with multiple addresses, for instance. In a larger building, a mapper might intentionally locate an address node near the entrance to assist with routing (though entrances can be explicitly tagged as well, see https://wiki.openstreetmap.org/wiki/Key:entrance).

IMO if the buildings you're seeing are simple single-address buildings, and you have personal knowledge that the building shape and the address are correct as currently mapped, then merging the address node into the building is probably a good thing. I would not do it in areas where you're not familiar with the quality and accuracy of the existing map data, or where using address nodes on all buildings is standard practice. When in doubt, try to contact active mappers from the local community!

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answered 28 Mar, 18:29

jmapb's gravatar image

accept rate: 22%

edited 28 Mar, 18:32


I would just note that there are a few parts of the world with open government databases that are regularly synced to OSM, and in some of those places they're rather insistent that the nodes stay separate to ease this process.

(28 Mar, 22:41) InsertUser

do they also prohibit to map addresses on POIs? What if the official database is wrong? We should not automatically “sync” (read overwrite) addresses from official sources

(29 Mar, 17:44) dieterdreist

There is not a simple answer to this question because addressing works differently in different parts of the world. Generally the “best” representation is putting the address to where it is assigned. If the building plot gets the address, a common way of representing it is adding the address to the buildings on the plot (neglecting the rest of the space, which is likely not relevant for most people anyway).

In some areas, building entrances and gates get the address, and in these cases it would be wrong to map them on the building.

In case the whole building has the address but in OpenStreetMap there is just a node inside the building with the address, it is better to move the address tags to the building outline, although it may not be worth it, from a dataconsumer perspective it is almost the same (unless there are things inside the building, like offices, shops, agencies, restaurants, museums, workshops, etc.).

It may also be better to create some redundancy by repeating the addresses on the things that use them (POIs like the aforementioned), rather than relying on topology alone (inheritance from the surrounding polygon), because things tend to be pushed around a bit, or positions may be approximate, and explicit, individually verified addresses are more stable.

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answered 29 Mar, 17:42

dieterdreist's gravatar image

accept rate: 3%


Adding addresses to both POI nodes and the buildings that contain them is another debate where there's "no simple answer." See a previous discussion at https://help.openstreetmap.org/questions/48735/address-information-in-poi-and-building with some good arguments on both sides.

(29 Mar, 18:34) jmapb
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question asked: 28 Mar, 16:32

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last updated: 29 Mar, 18:34

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