Hello, There are a lot of amenities that are not on the surface. Shops, offices, restaurants, cinemas... they could all be in street underpasses, subway stations and other kinds of underground tunnels. The first question is how to determine the exact location of these objects... GPS is not reliable underground. However photo-tagging, getting the tunnel construction plan (if available to general public) are all good to go. The second question is how to tag such amenities? What to add so it will be clear that the amenity is underground? underground=yes ? First I though of layer=-1, but this is more for rendering purposes. Any ideas here? asked 06 Mar '12, 08:05  ivanatora |
3 Answers:
You could perhaps use the level tag. answered 06 Mar '12, 09:24  EdLoach ♦ 'level' tag will just say that the feature has some underground basement. It will not say if the feature is buried or if it is the basement of a 20 floors skycraper. (20 Sep '13, 09:31) Pieren |
underground=yes or location=underground sound good. They accurately describe the situation. answered 20 Sep '13, 13:30  slover98 So does the already well-established level tag in my opinion. (20 Sep '13, 13:33) scai ♦ As mentioned above, the layer tag does not quite accurately describe the situation. You can have a feature tagged as Layer=-1, yet, it still may be above ground. (20 Sep '13, 14:04) slover98 1 Yes of course but I'm talking about the level tag. Don't mix layer with level, they describe different attributes. (20 Sep '13, 15:00) scai ♦ I see, my mistake. Still, I would say that even the level tag is not quite established, based on the wiki article about Levels, that states: On a single small feature which might be found inside a building, this tag denotes on which floor the feature can be found. Based on this it just denotes a location of a certain feature. (20 Sep '13, 15:20) slover98 |
This sub-level street https://www.openstreetmap.org/browse/way/31287202 ( Image: http://www.flitzsport.de/image/passarelle.jpg ) is tagged simply answered 20 Sep '13, 14:52  gormo |
This is a common misconception about the layer tag. Neither does -1 mean that the feature is underground nor does 1 mean that the feature is above ground. These values are just relative to other features.