[OSM-talk] [tagging] Feature Proposal - RFC - incline up down

[Morten Kjeldgaard]

Roy Wallace wrote:

> "Inclines are easy to calculate if elevation data is available" -
> that's a big if, isn't it?

Not really. There's a lot of elevation data available in the GPS traces, 
and since roads where incline=* is relevant are drawn along GPS traces, 
it's a matter of exploiting that data value. I'm aware that the GPS 
elevation data isn't terribly accurate on an absolute scale, but when 
determining inclines we will be making elevation differences which will 
decrease the error significantly.

> "hard-to-verify data" - I don't see why incline=* is any harder to
> verify than ele=* - as you said yourself, if you have one you can
> calculate/verify the other...

The fact that there's a lot of unreliable and hard-to-verify data is no 
good argument for adding more.

> "It would be much better to...design a system for registering
> topographical data" - sounds good, go for it. But I don't see a
> problem with using incline=* in the meantime.

Incline tagging is useless unless a consumer of this data can count on it 
being generally available. A driver might find herself on a steep incline 
when expecting a flat one, just because it wasn't tagged.

IMHO it is much more productive to spend time working out some system that 
would allow us to compute inclines automatically on the whole dataset. That 
would give you the desired data all over the world and not just in your 
local area.

Cheers,
Morten