Infer Building Height If Given Levels?

[youngpm]

Hello!

I am wondering if Overture would want to infer the height of a building when given the number of levels but not the height itself.

For example, in the explorer, if you zoom here: https://explore.overturemaps.org/#18.79/43.6466092/-79.3921981/0/57

There is a hotel composed of a bunch of parts, but it renders like a pancake because there's no explicit height:

This seems to be fairly common in Toronto in my clicking around.

[atiannicelli]

In looking into this a bit I see that the average height of a floor for residential (3-3.3) is different from a commercial building (3.9-4.5) and different still from hotels (3.75-4.2). Would we try to determine the type of the building to estimate height or just use a single average floor height (this would be my choice to keep it simple)?

Thinking about what the logic would be that is applied AFTER we get heights from lidar and other sources - if we used one value:
If height is null then set height to floors * 3.3
If min_height is not null then make sure it is less than the new height.

If we do this for num_floors to height then we should also add the same logic to min_floor to min_height.

Is there any consideration for underground floors/height?

[jwass]

I think we shouldn't guess a height from number of levels. This is mostly a rendering issue and consumers can make their own judgement call about what to do for a default IMO. When Overture includes a height, it's assumed it's actually a measurement. What value do we really provide by just multiplying by a constant?

[youngpm]

FWIW in poking around the old tilezen code, they did a 3 meters * num_floors + 2.

Somewhat unrelated, but in general there are many building/building_part combos that are mistagged in OSM (e.g. they didn't follow the simple 3d building guide and add parts that union up to encompass the entire building footprint) and so you can find a lot of UFO building parts (here's some in Seattle if you rotate around at bit)

IMO it would be great if Overture sanitized some of this when ingesting from OSM, its a nice value add and in this case, more difficult than just estimating a property. I think adding a height when there's other information to estimate it falls into the same category of data normalization, just one less thing for a consumer to work out on their own.