[OSM-newbies] Systematic shift between streets and aerial photo

[Clifford Snow]

On Sat, May 31, 2014 at 2:14 AM, Kjell Inge Tomren <kjell-inge at tomren.as>
wrote:

> I noticed there was a street name missing near my home and as my first
> edit i decided to add that name to OSM. The update was easy. I even did it
> from my tablet in bed this morning so i was inspired to do more. There are
> no numbers on the houses in my area, so i decided to register my own and I
> did it by pointing at my house in the background aerial photo and added the
> info for a house. But I noticed the position of the house was not correct
> vs the nearby streets.
>
> After a closer look I noticed that there is a systematic shift between the
> streets in my area and the background aerial photo. Then I´m a bit stuck.
> Which is correct positioned? The street positions or the background aerial
> photo? How is it possible to correct a systematic error like this?
>

There is an option to fix the background image in iD. Click on the layers
icon and then "fix alignment." However, for that you need a good reference.
Since there are only a few gpx traces, you might need other sources. Strava
(bike/run app) has a iD product in beta that uses their traces. You can see
a demo and use their slide iD beta at http://labs.strava.com/slide/. They
have something on the order of 200B gpx points. From looking at their
traces it does appear that the the Bing image is offset.

Slide works with your existing OSM id. You might give it a try. Once you
have the roads aligned with their gpx points you can use the roads to fix
the image alignment in the OSM iD editor.

Clifford


-- 
@osm_seattle
osm_seattle.snowandsnow.us
OpenStreetMap: Maps with a human touch
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