The latest tools in the City of Asheville’s GIS tool belt are lighter than air and float at 1,000 feet: Weather balloons outfitted with digital cameras are being used in the ongoing project by the IT Services Department and the Parks, Recreation and Cultural Arts Department to confirm and map the location of graves and plots at the city’s historic Riverside Cemetery.
The balloons provide aerial pictures of the cemetery grounds, which can then be matched with cemetery records and on-the-ground surveying of markers and landmarks. Together, all of this information provides an accurate survey of the grounds, which is being plugged into an interactive GIS map. Riverside Cemetery is managed by the Parks, Recreation and Cultural Arts Department and, alongside good stewardship, the mapping allows the city to know how many and where plots are available for sale on the grounds.
Recently, a class of third graders from Isaac Dickson Elementary School visited Riverside Cemetery to see how the balloons work and learn about mapping. The students got to see how pocket cameras were rigged with harnesses made from string and repurposed two-liter soda bottles so that they would remain pointed down and resist spinning, and even got a chance to “pilot” the balloons by holding the lines.
Working with Adam Griffith, a research scientist with Western Carolina University and the nonprofit group The Public Laboratory, the team launched two weather balloons, spooling out 1,000 feet of line to keep them from floating into near-space altitudes (where differences in pressure would cause them to pop). Each balloon carried a pocket digital camera set to take pictures every four seconds. Using this relatively inexpensive technique, the team captures photos within a 1/10-mile radius.
GIS Analyst Scott Barnwell says the technique could be used for other areas around the city as well as to fill in information gaps. Aerial images are taken regularly by the N.C. Geographic Information Coordinating Council (NCGICC) but the latest information is from 2010, and another fly-over isn’t planned until 2015. The balloons can provide images of changes and new construction in the ensuing five years, Barnwell says. And the images taken from the balloons show higher detail than existing satellite imagery.
As for the Riverside Cemetery survey, work mapping the graves is nearing an end. “We’re about 95 percent there,” Barnwell says. “We’re just working on that last five percent now.”