On Aug 17, 2016, at 2:00 PM, Florian Lohoff wrote:
[...]
(Florian Lohoff, I agree)
I can confirm the same problem, though I think this is a mix between
OSM, Nominatim and OSRM. We route from municipalities to airports. Where
that was available, we used the "Admin Center node" set in OSM, but even
that is often NOT a road address. We updated all airports to a street
address to avoid such conflicts on that side. We now have the task at
hand to define a "starting point" for any given municipality on file. A
major problem happened i.e. in the Alps, where the "centroid" is on the
mountain top, OSRM taking mountain ways at extreme slow speed adding
some 20-40 unnecessary minutes, comparing to the neighboring town having
an admin center defined.
And we can't blame it only to Nominatim: We use geodata as origin and
destination for the route as we found Naming to be extremely misleading.
I cannot recommend that at all. We had major errors, where the way you
entered the data had major impact on the accuracy of the identified
geopoint. We had i.e. Münster (Lech), naming according to Wikipedia and
the city, OSM relation/962251, with a population of 2000 mistaken with
Münster (Westfalen). A major city there. And a minor difference in drive
time by 570 km or 5:30h and a nice "hole" in our map in Bavaria until we
solved that... Other examples where islands with "exclaves" where the
centroid simply was in the water and the drive time started on the wrong
(uninhabited) island...
So yes, I think it would be wise to improve OSRM on this. It might be
needed to improve the OSM data, but moving streets or ways cannot be the
answer. If I understood those comments right we talk about "adjusting"
reality here for the sake of a route request...?
I'm also really concerned about that "indefinite distance" like on my
Helgoland problem. Found the same true on other islands. That way, OSRM
returns something where an error would make more sense! We can't solve
this in a day or with a quick fix, but this is a quality problem that
may have repercussions all over the planet(.osm). A general improvement
(a.k.a. evolution). Issue is (in my opinion) that there should be a
"best practice". And that might need the possibility to have an optional
"routing reference point" (whatever you call it) on places, ways or
points... If it's not there yet anyway?
How to proceed? I'm too new to say.
Cheers - Juergen
P.S.: Have been out sick. Sorry for the delayed response.
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