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#1 2018-03-17 03:11:04

Registered: 2018-01-09
Posts: 2

Poorly located 'ways'

Hi, this has probably been done to death, but I can find no direct reference with a search.

How much reliance can be placed on the underlying satellite imagery when marking things?

For instance, in the suburbs around where I live, many street intersections seem to be
shifted maybe 10 metres or more out of position, and the shape often does not closely follow
the actual street shape.  I assume this was done in bulk based on some kind of government
survey data. But some streets are correct within a metre or less - are these ones that have
been corrected? This seems to be the case with some I have checked. Or is it where the
surveying was done right.

This mis-alignment makes adding paths, points of interest, etc a bit tricky. In particular:-
1 - do we realign the roads to suit the sat. images?
2 - do we mark additional items as per the satellite images and forget the roads? or
3 - do we take GPS positions or tracks of everything and load that into OSM? so everything
     is offset (which does not seem to be the case, or
4 - do we try to offset everything according to the sat images?

My idea is to re-align roads, etc as per the sat images so that things like new tracks can be
joined up correctly.

Is there a standard for this? for correcting pre-existing markup.



#2 2018-04-11 22:38:17

Registered: 2018-02-02
Posts: 3

Re: Poorly located 'ways'

in short GPS traces are more accurate than aerial imagery and this is better outlined here - … r-location

There's a good amount of info out there on the wiki about this. in terms of why one is aligned and another isnt, if you look at the edit history you can see where the data came from and who edited it last etc. If you are in JOSM editor, just select the way and hit Ctrl + H.

Hope this is of use.



#3 2018-04-18 04:53:47

From: Sydney
Registered: 2011-10-22
Posts: 13

Re: Poorly located 'ways'

I think it depends on which area you're in, which imagery source you're using, and which kind of GPS trace you're using (some are better than others). Could you let us know which area you're looking at?


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