Philly Tech Week, now in its fourth year, brought numerous creative and inspirational events to Philadelphia. GeoPhilly, Philadelphia’s meetup for spatial and mapping enthusiasts, hosted a fun, educational event during the festival. Balloon mapping is a DIY and affordable technique for capturing high resolution aerial imagery and it puts the power of data collection in the hands of the data consumers.
This approach can be particularly helpful in times of disaster or urgency when it is too costly to capture imagery in traditional ways (satellite and low flying aircrafts). You can learn more about these methods in my 2013 blog on mapping techniques during emergencies and the Public Labs page about balloon mapping during the 2010 Deep Horizon Oil spill. Balloon mapping can also be used during gatherings, community events or protests to photograph the crowd such as Occupy Wall Street. Or it can be used for the mapping of public space such as the Benjamin Franklin Parkway in Philadelphia.
Engaging the Community
Balloon mapping is an easy way to engage the community by inviting participants to learn the methods and conduct their own balloon mapping exercise. The unique thing about balloon mapping, compared to drone mapping, is that it is very transparent: a large red balloon tethered to a person clearly shows that the mapping process is public and not hidden or secretive. This was evident at our balloon mapping event which had numerous passersby comment and inquire about the exercise. In this way, it engages community members and neighbors in the activity.
How does balloon mapping work?
A 5ft diameter balloon is filled with helium (a 80CU tank is sufficient for one balloon) and attached to approximately 1000 ft of cord which is tethered to a moor (either a very heavy object or a person). The balloon has a camera rig attached to the base which holds the camera steady. The camera is programmed to automatically snap photos at regular intervals. The balloon is raised in the air, though always tethered, and continuously collects high resolution photographs of the area. Kite or pole mapping can also be used to capture photos from above. The photos are later downloaded and stitched together using reference images and open source software MapKnitter.
The images captured by our balloon mapping exercise are free for anyone to access and enjoy. You can find all the photos taken during GeoPhilly Balloon Mapping on google drive, along with instructions, a video and other resources.
You can still get involved, even if you don’t organize a balloon mapping activity. The open source software MapKnitter can be used by anyone to stitch together the photos taken at other DIY aerial mapping activities. You can contribute to other projects by helping out with stitching.
Special thank you goes out to the Delaware River Waterfront who allowed us to use their space for this activity. Also special thanks to Azavea for funding this event and for all the attendees who participated and helped stitch the photos together.