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#1 2010-11-30 23:05:16

stephankn
Moderator
Registered: 2010-05-04
Posts: 621

Warning! Bing aerials misaligned

Warning, the aerial images from Bing do not seam to be aligned correctly.
Do always check with GPS tracks in that area that the alignment is right before using it to derive geometries.

In the near future there should be tools available to fix the alignment problems of the aerial images.

See the following screenshot for an example (click to zoom):

bingmisaligned.th.jpg

Stephan

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#2 2010-12-08 23:31:10

stephankn
Moderator
Registered: 2010-05-04
Posts: 621

Re: Warning! Bing aerials misaligned

I have added all known areas of Thailand with Bing hi-res aerials to the coverage page in the wiki.
http://wiki.openstreetmap.org/wiki/Bing … e#Thailand


Most areas need a comparably big alignment of the image.

Right now we miss reference points on the ground that have a precise known position and are clearly visible on the aerial images.
For the Chiang Mai areas search for "Wat Doi Saket" and align the buildings with the aerials. Johnny Carlsen and I both independently aligned the aerials according to existing GPS tracks and got a matching building outline.

If you align try to use GPS tracks as reference on an area with open sky, so not downtown city. Try to align against multiple tracks from different users to average out errors.

Adjust using Potlatch2 (hold space and align) or JOSM Imagery plugin (adjustment icon in sidebar)

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#3 2011-01-23 19:24:41

stephankn
Moderator
Registered: 2010-05-04
Posts: 621

Re: Warning! Bing aerials misaligned

Bing imagery was recently updated. Now large parts of Thailand are covered.

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#4 2011-01-24 15:36:16

Willi2006
Member
From: Khon Kaen, Thailand
Registered: 2009-12-12
Posts: 421
Website

Re: Warning! Bing aerials misaligned

Great, I didn't expect this in the near future. Most of Khon Kaen Province up to zoom level 18. Same as Google, but newer, 2008 or even 2009. The shift differs already within the city. But many highways are already in OSM based on GPS traces for adjusting the images. Time to start rethinking about my mapping methods and projects.

Last edited by Willi2006 (2011-01-24 15:51:42)

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#5 2011-01-24 17:15:18

DuiNui
Member
From: Chiang Mai, Thailand.
Registered: 2009-08-04
Posts: 41

Re: Warning! Bing aerials misaligned

I can't get Bing to work at all at the moment.
First time I've tried, but all I get is a white background.
Is there any set-up I need to do?
I kinda thought it should just "work" according to the wiki entry on it.

Thanks for any help.

Dui.

Edit:
Should have been more specific, Bing in JOSM...

Last edited by DuiNui (2011-01-24 17:26:51)

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#6 2011-01-25 00:53:49

stephankn
Moderator
Registered: 2010-05-04
Posts: 621

Re: Warning! Bing aerials misaligned

Here you can activate a layer showing the coverage:
http://nametool.osm-tools.org/

With JOSM running it provides a single-click option to load the displayed area inside JOSM (you need to activate RemoteControl first), the globe button top right on the web page when zoomed in enough.

@Dui: Use a recent "tested" version of JOSM. In the top menu select "Imagery/Bing sat". Works without additional downloads. If it's still not working check the console for error messages.

Stephan

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#7 2011-01-25 08:01:26

DuiNui
Member
From: Chiang Mai, Thailand.
Registered: 2009-08-04
Posts: 41

Re: Warning! Bing aerials misaligned

Thanks Stephan,
I opened Josm with a console window and when I activate Bing the console dumps:
Got an attribution image 29x93

That's it, no errors or warnings and no imagery.
I googled it and it seems others have had the same problem, but as yet I cannot find a solution to it.
Anyone here got any ideas?

Thanks

Dui.

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#8 2011-01-25 14:05:20

DuiNui
Member
From: Chiang Mai, Thailand.
Registered: 2009-08-04
Posts: 41

Re: Warning! Bing aerials misaligned

Found my problem.
Both the max and min zoom were set to 2 in the wms plugin preferences...
I had to download and debug the source to work that one out, it's not something I've ever changed, god knows why it was set like that.
Important thing is it's ok now.

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#9 2011-05-10 19:31:44

Bernhard Hiller
Member
Registered: 2011-05-10
Posts: 1,052

Re: Warning! Bing aerials misaligned

Hi Stephan,
do not worry so much about that misalignment. Looks like less than 10 meters to the West and 5 meters to the North.
True, it is disturbing when tracing. But on your GPS you will hardly ever see it: at common resolution, the lines used for showing the roads are bigger than that!
Consequently, let us continue tracing their images, as most areas of Thailand are still hardly mapped at all. Meanwhile I have traced most roads between Ranong and Krabi along the Andaman coast, try it on your GPS, and tell me how much you were disturbed by the Bing offset...
Have a lot of fun!
Bernhard

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#10 2011-06-02 11:54:24

stephankn
Moderator
Registered: 2010-05-04
Posts: 621

Re: Warning! Bing aerials misaligned

Hello Bernhard,
The misalignment varies. Some times you can see the result of the aerial image stitching and rectification process. Just try to be as accurate as possible. This saves a lot of time later.
Even when you don't see the accuracy on your unit, the mapmatching engine inside will give a lot better results when the underlying data is more accurate.
Stephan

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#11 2011-06-12 13:04:46

Willi2006
Member
From: Khon Kaen, Thailand
Registered: 2009-12-12
Posts: 421
Website

Re: Warning! Bing aerials misaligned

Bernhard Hiller wrote:

...
do not worry so much about that misalignment.
...
Consequently, let us continue tracing their images, as most areas of Thailand are still hardly mapped at all. Meanwhile I have traced most roads between Ranong and Krabi along the Andaman coast,
...

Looking at this area: There are hardly names or highway numbers. The highway classification is based on what. A lot of data, few information. I'm wondering for which purpose somebody might use such a map. The blank satellite images contain more information.

Imho, more information, not more data is needed. I worry about that much more.

Willi

Last edited by Willi2006 (2011-06-12 13:05:37)

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