On the map here there is a 7-10 meters shift along the latitude axis to the west. The problem is, it isn't only with the tram tracks(thanks to them I can't map an asphalted footpath along them, because it overlaps with the rails while it should be to the left of the left rail), it is with only some places scattered all over Ukraine. Could you please say why some places such as here, here there is a shift while there there is minimal or even none?

asked 15 Jul '16, 06:49

Ukraroad's gravatar image

accept rate: 0%

edited 15 Jul '16, 06:52

aseerel4c26's gravatar image

aseerel4c26 ♦

How did you get your real position assumption? From the aerial imagery in the background? It may be the one which is shifted. But also the opposite could be true: the OSM data is shifted (usually due to shifts in aerial imagery some years ago).

The offset can vary between regions and even locally in case of mountains.

Likely you want to compare to averaged GPS data (e.g. OSM-uploaded GPS traces or strava – quite some data in your area) as a reference.

Unless you have that or know otherwise what's closer to the real position you should move (align) the aerial imagery (in your editor) to match the existing OSM data and then do your edits.

Please see https://help.openstreetmap.org/tags/alignment/?sort=mostvoted and https://help.openstreetmap.org/tags/offset/?sort=mostvoted or https://wiki.openstreetmap.org/wiki/Using_Imagery for more info.

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answered 15 Jul '16, 06:58

aseerel4c26's gravatar image

aseerel4c26 ♦
accept rate: 18%

edited 15 Jul '16, 20:36


see https://help.openstreetmap.org/questions/6385/alignment-of-track-vs-background-imagery you need several GPX traces to be confident before dragging the aerial into alignment.

(15 Jul '16, 10:59) andy mackey

Problems like this are easier fix if we upload our traces as public. We can average them to get better fix. There are a few north south traces but are they rail travelers (probably) or cyclists and walkers?? on the path.

(15 Jul '16, 11:09) andy mackey

@andy mackey: just to clarify (for newbies): also tracks uploaded with the visibility option "private" help for the issue mentioned in this question.

(15 Jul '16, 19:26) aseerel4c26 ♦

To further clarify that clarification - private traces aren't visible in iD, only in JOSM and P2 (and in fact there's been an outstanding issue with no new traces appearing in iD - see the relevant bug tracker).

(15 Jul '16, 19:29) SomeoneElse ♦

@SomeoneElse: thanks, oh, really? I did not know that. Sorry, I am a newbie to iD. ;-) Nobody was speaking of iD, were them? ;-)

(15 Jul '16, 20:35) aseerel4c26 ♦
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question asked: 15 Jul '16, 06:49

question was seen: 1,128 times

last updated: 15 Jul '16, 20:36

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