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buskerudbyen / cycling-norway

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Elevation data check: Height of bridges is missing? #78

Open tsobuskerudbyen opened 1 year ago

tsobuskerudbyen commented 1 year ago

Checked data from Tromsø (I'm going there next week). The bridge going over the sea into the island that it is the city of Tromsø is at least 38 meters high. But the route here is displaying only 12.91 meters.

See info on the bridge: https://en.wikipedia.org/wiki/Troms%C3%B8_Bridge

See that other routs locally looks okay. Is this difference because it is a bridge, and not landmass. Hence, we are missing elevation data here. Something that can be done about this. An OTP issue maybe?

leonardehrenfried commented 1 year ago

The Entur service where we get the elevation data from doesn't appear to have elevation data for this bridge:

image

(The green, blue dots indicate that data exists.)

I'm not sure if the satellite ignores everything that isn't on land or whether it doesn't have a high enough resolution to "see" the bridge.

tsobuskerudbyen commented 12 months ago

Strange that this is data that comes from Kartverket. Norway has a lot of bridges like this. Did not find anything on https://wiki.openstreetmap.org/wiki/Key:bridge, but is https://wiki.openstreetmap.org/wiki/Key:ele an option? Can we ask the OTP community/Entur people? If the latter who would know?

leonardehrenfried commented 11 months ago

I've read some code in OTP that can read the elevation from the ele tag but I've never actually tried it. I suspect that it's not working as intended but I can fix that.

tsobuskerudbyen commented 11 months ago

Great. Please bring it up in your next OTP meeting. Always good to have an idea if others have thought of this, solved it in other ways, and – then if not solved from before – if our suggestion is the best one. There may be other data or tags that are better for this.

tsobuskerudbyen commented 5 months ago

@leonardehrenfried Any news here?

tsobuskerudbyen commented 3 months ago

No idea if it is relevant, but found this from a 2012 OTP presentation

Elevation . . . bridge=yes or tunnel=yes: fill in elevation from connected nodes OSM ele tags fill in gaps (e.g. bridges)

So, it seems, based on the documentation I have gathered from e.g. #125, that the first point is also lacking. (The second point - about the ele tag - @leonardehrenfried quessed over is missing.)