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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's gravatar image

accept rate: 7%

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.

(20 Sep '13, 09:36) scai ♦

underground=yes or location=underground sound good. They accurately describe the situation.

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answered 20 Sep '13, 13:30

slover98's gravatar image

accept rate: 5%

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

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 ( Image: ) is tagged simply layer=-1.

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answered 20 Sep '13, 14:52

gormo's gravatar image

accept rate: 13%

You could perhaps use the level tag.

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answered 06 Mar '12, 09:24

EdLoach's gravatar image

EdLoach ♦
accept rate: 22%

'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

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question asked: 06 Mar '12, 08:05

question was seen: 6,587 times

last updated: 20 Sep '13, 15:20

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum