What is the difference between "height" and "building:height" keys?

OSM Specials OpenStreetMap 3D
#1

I am confused about the difference between these two tags: “height” and “building:height”. And which one of them should be used to specify the height of a closed way representing a building?

I tried googling but the key:building:height page keeps redirecting me to the key:height page.

Does that mean that the “building:height” key is a bit old, and that it is recommended to use the “height” instead?

I still see some of the closed ways use it. Like this one:
http://www.openstreetmap.org/way/24273222#map=19/52.52124/13.41634

Thank you for the reply.

#2

building:height is more or less used as 3D building key which can be used to define the height of a building without roof, if there is anyone. roof:height defines then the height of the roof. Both together make the height.

#3

Thank you for the quick reply R0bst3r!

Then what would be the difference between the following keys:

  • min_height
  • building:min_height
  • roof:min_height

?

#4

There is no need to use building:height and building:min_height.
Use height and min_height instead.

roof:min_height has no meaning. The vertical position of the roof is completely defined by the tags min_height, height and roof:height.

The lowest point of the roof is therefore located at z = height - roof:height
The highest point of the roof is located at z = height

By the way we have a dedicated sub-forum for 3D features of OSM:

#5

In short, simply forget about building:height and building:min_height :slight_smile:

#6

Maybe a short overview with examples can give: http://wiki.openstreetmap.org/wiki/Simple_3D_buildings

#7

I did not know this kind of question should go to the 3D section. I apologize.

Thank you R0bst3r. I checked the article and interestingly it does not mention neither ‘building:min_height’, ‘roof:min_height’

Does this mean that ‘roof:height’ is actually the ‘min_height’ key used for roofs?

I am still confused. The dome of the BCC Berlin congress center has ‘building:height’ and ‘building:min_height’ keys:
http://www.openstreetmap.org/way/19001901

Should both of them be replaced with: ‘height’ and ‘min_height’?

#8

Building:min_height is equal to building:min_level, they describe in different ways the lower end of a building, e.g. of a bridge between two buildings.

roof:height is the lower end of a roof to the top. A flat roof has 0, a gabled roof with 1 floor level maybe 3 (in meter).

To make 3D mapping easier I use often only building:min_level, roof:levels etc.
You see, you get into advanced mapping area which is a little more complicate than just mapping 2D areas.

#9

I am going to be banned for constantly asking questions, these keys are really confusing me.

Should I or shouldn’t I use them?

#10

It’s not a good idea to use unconvetional tags that aren’t documented in the OSM wiki.

building:height and building:min_height must be replaced with height and min_height.

In some case there are both building:height and height. In that case building:height must be deleted.

#11

No! Use only the tags documented in the OSM wiki.

#12

This means that if there is no specific page (like no page for key:building:height), which describes a certain tag, I should not use that tag?

Understood.

Isn’t the lowest point of the roof defined by ‘min_height’ key?

For example the BCC Berlin congress center’s dome has the following tags:

‘building:min_height’ (should be ‘min_height’ as you told me): 8 meters
‘height’: 16 meters
‘roof:height’: 8 meters.

#13

The page in the OSM wiki reflects some consensus among OSM community on how to tag specific features. So one should stick to the OSM wiki.

In this particular case the lowest point of the roof coincides with the lowest point of the building part, since the building part doesn’t have walls:

The lowest point of the roof is z = height - roof:height = 16 - 8 = 8, which is exactly equal to min_height.

#14

Thank you vvoovv.
Why is this a specific case? Can you please provide an example of some more common case? I sort of understood you that this case is somewhat specific. I would be grateful for that.

#15

It’s specific case, because the building part doesn’t have walls.

The height of the walls is height - min_height - roof:height = 16 - 8 - 8 = 0

To get walls for this building part increase height or decrease min_height or roof:height.

#16

I didn’t understand you.
Why do we need to get the walls?
This building:part (19001901) is a dome. The height of the dome is 8 meters, 8 meters from the ground (so there are 16 meters from the ground to the top of this building:part). Is this diagram correct:

?

If this building:part would have walls, the height of those walls would still be: height - min_height

Did I get all of this wrong?

#17

Your image is correct for the building part 19001901

Please refer to Simple 3D buildings.

So height - min_height is equal to the sum of the height of the walls and the height of the roof

The height of the roof is just roof:height.

The height of the walls is therefore height - min_height - roof:height

If the height of the walls is equal to zero as in the example, that means there are no walls, only roof.

#18

Thank you for the reply vvoovv.

I still do not understand you.
What walls? Where are they located? The building part 19001901 has no walls.
I apologize for insisting on this walls issue.

#19
#20

Thank you vvoovv. I don’t understand it. I won’t insist on this anymore.
I still do not understand how did we end up with walls. They are not mentioned among the keys of the 19001901 building part. I haven’t asked about the walls either.
Maybe the walls are somehow connected with ‘roof’ keys, and I am not aware of that.

Thank you for your patience and replies.