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#1 2017-07-11 16:06:16

Lea27784
Member
From: Freiberg/Saxony, Germany.
Registered: 2015-03-20
Posts: 137
Website

Slovenia: Dislocation in comparison to satellite image

Hello,

during my holidays I have mapped a bit in Slovenia and I found out that most mapped areas seem to be dislocated in comparison to the satellite image :-( For example, I've uploaded a GPS track in a wood (http://www.openstreetmap.org/user/Lea27 … es/2445899). I know that my boyfriend tried to correct some areas, but I'm not sure if this is the right way to improve OSM, as I don't know what's the reason for the dislocation (satellite imagery? former gps traces??).

Can you help us please?

Kind regards from Germany.


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#2 2017-07-12 11:47:16

coloredstone
Member
Registered: 2014-02-08
Posts: 25

Re: Slovenia: Dislocation in comparison to satellite image

Dear Lea, is it so that a dislocation (offset) of satelite images is quite a common problem? It seems you have mapped this track (highway=path) quite "correctly" - you have adjust it to other OSM elements, especially landcover elements.

These elements are mostly imported (see: https://wiki.openstreetmap.org/wiki/Slo … _RABA-KGZ) and can usually be used for the correction of the satelite images dislocation. In most cases imported elements have better (or more correct) position than standard mobile devices GPS tracks or satelite images with no offset. In that case they shouldn't be changed (better adjust offset).  Of course this is not always true, especially when situation has already changed from the time the landcover import has been done.

Thank you for your question and contribution to OSM in this area. If you have more questions related to the particular areas, please put it on and someone might have more knowledge of the local situation.

Best regards,

Coloredstone

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#3 2017-07-12 12:10:18

Lea27784
Member
From: Freiberg/Saxony, Germany.
Registered: 2015-03-20
Posts: 137
Website

Re: Slovenia: Dislocation in comparison to satellite image

We have noticed the dislocation in several areas in Slovenia and not only in built-up areas but also in the wood for example.

Thanks for the tip with the RABA-KGZ - when I open JOSM it is even shown in the background images big_smile Yeah, I mapped the path as a compromise between satellite image, the already existing mapped elements and the GPS track. But now I see that the already mapped elements are nearly congruent with the RABA-KGZ (and are only dislocated in comparison with the satellite imagery) - perfect! This will help me in future to decide if some areas have to be improved concerning their position or not.

So, for the elements within one RABA-KGZ area I have to check in which direction I have to "dislocate" the element manually, in order to make it "fit".

Thank you for your quick help! :-)
Lea27784

Last edited by Lea27784 (2017-07-12 12:12:49)


Meine Profile: OSM | OSM-Wiki | Mapillary | Transifex
** Bitte immer über diesen Link auf Amazon einkaufen, dann geht eine kleine Spende an OSM! **

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