Public Lab Research note

GSoC Update - AutoKnitting 2

by xvidun | July 03, 2014 05:47 03 Jul 05:47 | #10648 | #10648

My attempt and results

Continuing from my previous auto-knitting update, I have gone further successfully able to correct image based on rotation and scale.



The selected image had it's EXIF removed, so it follows "regular placement".

Different sample.


The rotation correction is not perfect for this sample as the above image uses "Magnetic North" as it's reference unlike "True North" which is used by most modern GPS. Finding "magnetic declination" looks difficult to solve for now, so I've left it aside.

I've tested scale correction based on altitude with ranges from 200's-500's m, it works well, I'm not sure how it is going to respond to extreme altitudes, someone will probably get their balloon really high!!.

Also for altitude correction I'm using FileReader API to get the original dimensions of the images, See Supported browsers.

Code: auto-placement

Next steps

  1. Update "create map" page to support GPS data from images, from the discussion.
  2. Try to work on "Magnetic reference".
  3. Move the "new mapknitter" to beta pages.

I've been a little slow for a few days for travelling and going some places, I'll work on catching up.


Finding "magnetic declination" looks difficult to solve for now, so I've left it aside.

Haha, true enough and this rough placement is already exciting!

I'd love for you to get this running on a test server, and to see how you've integrated it. Are you in touch with Dogi on the chat channel ( Can you ask him if you could have access to (i think you've already sent your public key).

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real neat to see! the image placement is close, except for that rotation problem. Definitely a big help to prepping a map!

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It seems to be working for me-- I don't have a gps-enabled data set yet though-- will have to go out with Skycam.

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@mathew, I'll be trying soon!! also for testing you could try @jeff's wiki here.

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