New York Magazine commissioned this map of ‘sluttiness’ in NYC based on OK Cupid (the dating site) data. Curious.

The wind was so strong that our first kite, carefully made that morning from dowels and Tyvek, shattered immediately. Instead, we launched a small soft kite with an iPod nano attached to it. Here’s a stitched image of the video footage we captured:

See all the pictures on Flickr.

The iPod has an SD camera which can capture many hours of video – and it’s so super light that we can fly it on a pocket kite. Many of the frames are blurred and the resolution is pretty poor (we’d thought of using a Flip camera but they’re more expensive and heavier) but when you go through the footage frame by frame you can find lots of good images. We then stitched these together with Calico and got the above image. It helped a lot to put a small ‘sail’ on the back of the iPod so it didn’t spin as much.

Everyone was cold but once we started flying the kites we all got really excited. The owner of the land was there with his kids and they helped assemble the rig and fly the kite:

The mapping was a big success – everyone ‘got’ why we were doing it, that documenting the tree planting and how they’re changing the landscape is a form of testimony. We’re still working to rectify the imagery, and I’d like to ask folks if they have any ideas – the stitching software we’re using assumes images were taken from a single viewpoint, but the kite and camera were moving all over the place. As you can see above, the stitching distorts things and we lose a lot of detail – how can we reconstruct a high-res image that assumes multiple perspectives? I’m looking at this tutorial to start with. We’re also thinking about an algorithm to dump the clear, undistorted and unblurred frames from a movie file. Ideas?

Update: We’ll be adding this material to the Grassroots Mapping wiki, where we’re putting together a comprehensive guide on low-cost participatory mapping techniques. Our hope is that we can offer a Grassroots Mapping Kit which people can use to reproduce these techniques to explore and document their own geographies no matter where they are.

Cross-posted with the Center for Future Civic Media blog

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.

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

Nice rendering, but not a new idea.

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