Grassroots Mapping: Balloon test #3 success

Josh Levinger of GroundTruth and I tested our larger 8 foot balloon yesterday, and it was a huge success! We ran all the way through our spool of string, and got some great images before the light got too dim. I rectified them using Map Warper (fantastic!) and we now have a mostly continuous ‘scan’ of our flight.

Screen shot 2009-11-19 at 11.04.31 PM

This means this can be a viable way to capture high-resolution geolocated imagery at low cost! I spent under $100 on the equipment – $30 for the balloon, $40 for the camera, $5 for the helium, and a few bucks for string. I bet it could be done for under $50 with a cheaper camera and perhaps trash bags instead of latex balloons. We’ll be trying that soon – I’d guess we need about 10 of these 98-gallon bags. I also turned the ISO way up for this because the light was failing, so the photos are pretty grainy. This camera doesn’t have shutter speed settings, though I’m still playing around with the CHDK settings so maybe I’ll do better next time.

I’m excited to test this in an area that really does not have good aerial imagery, like outside Lima, Peru.

See all the pictures at full resolution here: Balloon aerial photography on Flickr

See some great photos from the ground by Christina Xu on Flickr

7 thoughts on “Grassroots Mapping: Balloon test #3 success”

  1. Jeffery,this rocks!

    Yes, absolutely it has great potential in hard to reach, cash-poor places. Would be interesting to see the comparison of kite photos and balloon photos. I’d think that balloon photography would be more stable?

    (I love the hi-res official looking jacket too)


  2. Awesome! I chatted to OpenStreetMap people about this idea a while ago, but wasn’t being serious. Turns out it works!

    I was imagining colourful party balloons, but your big weather balloon along with the hi-vis jackets definitely makes this look more official.

    I was also trying to imagine what the limiting factor is heightwise. If you tied together more balls of string, how high could you go? Does the weight of the string limit it? Use thinner string? Fishing line?

  3. String is not super heavy… we actually just ran out of string. The 8-foot balloon has great lift and we only filled it to about 6 feet so as not to waste helium.

    Some notes I sent to Tim that might be useful:


    The photographs took about 2-3 hours but we could have done it faster… we were having fun. I’m using a Canon PowerShot A530, but it has no shutter control so something a bit newer would be best. it was $40, and I used the CHDK: Rectifying took about 2-3 hours too.

    I’m wondering if there’s some way to generate a high-res warped image… maybe this is another reason to move to canvas, so it could be done on the client side, base64 encoded, and uploaded again… Thoughts? Is Map Warper available at some repository so I could fiddle around with it? Or is there a REST API?

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