As the Engineers for Exploration Summer REU program drew to a close, we set out for one last mission: to perform an aerial survey of a restoration zone in Del Dios Gorge. Our collaborator from the San Dieguito River Valley Conservancy, David O’Connor, wanted to investigate the regrowth of native plants in the area where invasive eucalyptus trees had been taken out. With our balloon surveying platform and structure from motion reconstructions, we can capture a snapshot of the area at one time. In this case, we captured the state of the plant life, enabling an accurate assessment over time of change in the environment over time, be it the growth of native plants, or just a comparison populations of native and non-native plants. By repeating the survey in the future, we hope to help the San Dieguito River Valley Conservancy monitor the regrowth of Del Dios Gorge.
After getting set up in the parking lot, we began our trek through the rough terrain we were to survey, featuring uneven rocks, somewhat dense undergrowth, and trees that could snag the balloon’s tether. So off we went, hiking around and snapping pictures of the area from above. 8 hours later, the balloon had floated over 8 miles, and we had over 3000 pictures of the area to process.
After weeks of processing, we are excited to present high resolution orthophotos of the surveyed area. Orthophotos are pictures which are corrected for distortion so that distances measured in an image reflect actual distances on the ground. By combining this with location metadata from each image, means we can pinpoint the GPS positions of individual plants without stepping out of the office.
I’d like to thank David O’Connor for providing us with this opportunity, as well as all of the summer REU students for making this deployment a success.
For more photos of our trip, see Jennifer’s flickr gallery