[OSM-talk] Questions about levels and fractional levels as well as how to handle them.

[Martin Koppenhoefer]

2017-12-21 17:47 GMT+01:00 Colin Smale <colin.smale at xs4all.nl>:

> Hallo John,
>
> A level is not a unit of measurement like a metre or a kilogram. If level
> 1.5 exists, it only tells you that it is between level 1 and level 2. If a
> landing on a staircase between level 1 and level 2 is to be assigned a
> level, it wouldn't make any difference if you called it 1.1 or 1.9, unless
> there are other fractional levels around of course. It is the sequence of
> the levels that is important.
>


exactly, also because we almost never give level height information (e.g.
from the floor to the floor or roof above, or from the floor to the
ceiling. While the latter can be easier to survey, the former is easier to
build a simple model on). Typical floor height depends on usage, standards
(e.g. raised floor and dropped ceiling) and local regulations (minimum
heights according to usage).

As you asked for it, you can see the distribution of actual values in
taginfo: https://taginfo.openstreetmap.org/keys/level#values
0.5 (0.35% of all level values) and -0.5 (0.34%) aren't completely rare.

Cheers,
Martin
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