Public Lab Research note

Results: Simple Aerial Photomapping session, EWB Regional Workshop

by patcoyle | November 01, 2012 05:24 01 Nov 05:24 | #4725 | #4725

I did a workshop at Engineers Without Borders Regional Conference at Cal Poly on 10/20/12. I've done this last three years, on the Peninsula, at YouTube's HQ, in Portland, and now at Cal Poly. I also presented a poster at EWB-USA International Conference.

Stewart Long and I talked about it and I incorporated his tips. He said the 90 minutes for my session will go by in a flash. Get ready ahead of time. Get balloons or kites ready, rig attached, be ready to go. I did this. Echoes lessons learned from my past workshops where it took too long to get set up. Be sure all who want to fly the rig get a chance to do so. Feel it. With balloons it's palpable, with kites, seriously, oh yeah! Also, fly first, get images; then come back and look at the vugraphs, talk through the content, BUT the key is to start making the map with Knitter, then after a few images are placed, export it. Show how it's done, end-to-end with real live data.

I got Mac set up to project, student got me logged in so had internet access, then I added a slide that was displayed on the projector, saying, " We're outside flying, catch up with us. We’ll come back and try to make map. Look at the rest of the talk."

We did a sign-in sheet with a Safe Plan of Action (SPA), all asked to think about what was the worst that could go wrong, what the hazards were, and how we'd address them. Cathie Leslie, EWB-USA Executive Director, came by, suggested vest for traffic visibility in the street. Despite my suggesting he come on camera, she was not there long enough for us to capture her in our 8 second image intervals.

We flew the Kickstarter kit balloon. It took a whole 80 scf tank of helium (helium shortage is a whole different story, but I got it just in nick of time). Canon A490/495 vis/ir pair shot synched images every 8 seconds, triggered by TimeFugit iPhone app, driving CHDK USB remote shutter. We captured over 180 images.

We came into the classroom, went through the talk , opened up Knitter and started placing a few images, one of the participants came up and drove as we did the process; selecting a few images, placing them, scaling, rotating, skewing them; then we exported the map.

Our gps track from iPhone App, GPS-Trk, didn't function properly and I still need to trouble shoot what went wrong. Jeff Warren put the images up on MapMill so we were able to collaboratively score them, then work together to put them in the map. Highlights follow:

Link to presentation: Simple Aerial Photomapping session, EWB Regional is at:

Link to ground-based photos from our session are at:

I'm pleased to see people have been adding more images to the visible image map at:

The NDVI images (courtesy of Ned Horning's ImageJ/Fiji plugin) map I made is at:

A couple of examples of auto-processing of the images from our session are at: is from a commercial desktop package, Autopano Giga image stitching software from Kolor. is 3D model of subset of 5 images from free web-based It balked at the whole set and didn't take the NDVI images, which have been stripped of their EXIF info in processing.

I'm really pleased. We got nice mapping results. It is interesting that the Google Earth imagery for the area around the Construction Innovation Center is older, taken during contraction. Same in Google Maps until you zoom in further, then get up to date 3D imagery. So we have maps with more current information than Google Earth.

I'm traveling to New Orleans this weekend for Public Laboratory Barnraising/Conference. The emphasis is on "doing stuff together" rather than just presenting/talking. See:


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