"What exactly did you say you were trying to do again?" the ranger asked me as we stood on a seawall at Fort McHenry, taking turns winding in hundreds of feet of kite string attached to a nine-foot kite.

The kite, a nine-foot delta wing, had landed near a channel marker buoy and was now a nine-foot delta wing sea anchor. Tethered to it was a modified plastic food container encasing a very wet Android phone that was never intended to be a submersible. As we pulled the kite in, I asked myself the same thing—what the hell was I doing?

What I was trying to do was replicate what the military, government agencies, and private companies typically do with satellites, aircraft, and drones: get a bird's-eye view of the Earth's surface and create a photographic map.

Instead, my attempt at do-it-yourself aerial mapping quickly turned into a fiasco involving a squadron of US Park Service rangers, a few dozen puzzled tourists, and the flagpole that stood where the Star Spangled Banner once flew. I only mapped the limits of my own sense of humor, the patience of the National Park Service, and the contours of the bottom of the Patapsco River. An effort I planned since August was starting to look like a complete failure.

Fortunately, dear reader, I am not easily deterred.

A short lesson in how not to do aerial photography with a kite.

Taking back the skies

"Everybody needs maps, and being able to make your own map is important," Stewart Long, director of geography and data for GonzoEarth mapping services, told me before I had set out on this mission. Long has been doing aerial camera cartography for years, and he's one of the cofounders of the Public Laboratory for Open Technology and Science (Public Lab). It's a nonprofit organization that develops open source, do-it-yourself science tools—tools that have been embraced by environmental scientists, students, and activists.

Public Lab publishes a collection of resources for DIY aerial photography and mapping, as well as instructions on how to create other low-cost tools for environmental science. The organization sells pre-packaged kits through its Web store to help kickstart would-be aerial cartographers in getting their balloon- or kite-based sensor platforms into the skies. A kite from one of those kits was precisely what I was hauling out of Baltimore's shipping channel that November afternoon.

The importance of being able to create your own maps may not be immediately obvious to most people. Google, Apple, Bing, Garmin, and others have made turn-by-turn directions and bird's-eye views into a commodity. But the issue of who owns the skies above us and the images of the Earth we travel is one charged with increasing political baggage—especially as we face a future with skies filled with persistently watching drones mapping the movements of everyone below.

Using commercial maps carries a price tag—whether it's an actual dollar cost or the cost of having what we can see about the world filtered through a government's or company's point of view. Google and Bing have turned satellite and aerial imagery into a commercial geospatial information service that can transform where you are into an advertising platform. Local governments use aerial mapping to check for building code violations and assess property taxes. And increasingly, national governments are "mapping" in a different way, keeping a steady eye on the world below to track the movements of groups and individuals.

But in the hands of citizens, mapping can be a powerful tool as well. It can help us understand what's happening in the environment around us. Mapping is a journalistic tool and a tool of public accountability. With cheap, off-the-shelf components, individuals can create aerial maps for everything from documenting disasters to locating the sources of environmental pollution.

Public Lab's mission was born out of the necessity for such imagery. Starting in the summer of 2010, Long and others affiliated with Grassroots Mapping, a precursor effort to Public Lab, put together kits to help volunteers map the environmental impact of the BP Deepwater Horizon oil spill on the Gulf Coast. "Since 2010, we've mapped over 100 miles of shoreline in the Gulf region," he told me.

Since that effort, other scientists and environmental groups have adopted these techniques of DIY aerial mapping to collect a wide range of data. For example, one of Public Lab's efforts to create low-cost near-infrared digital photography for citizen scientists is giving scientists and farmers what amounts to a poor man's Landsat—a way to monitor vegetation health.

Even NASA has adopted some of the DIY techniques used by Public Lab for its own aerial mapping efforts. At a drone conference this past summer, an engineer from NASA's Goddard Space Flight Center told me that his team was using kites towed behind boats to do coastal mapping. The attraction is easy to explain: kites are relatively cheap, and they can fly over areas where even government drones can't yet fly. And while there are public sources of terrestrial imagery from satellites (such as NASA's MODIS data), their image resolution is limited—plus, satellites can't take pictures under the clouds.

Most commercially available high-resolution satellite and aerial imagery can be expensive to license. And few individuals or small organizations can afford to hire a plane to fly a photographic mission, let alone build their own spy satellite. Even if you have the resources to buy geospatial data from a commercial provider or put your own airplanes or satellites up to collect it, there's still one compelling reason to use the up-close and personal approach of DIY mapping—timing. DIY aerial photography allows for the collection of images on a schedule dictated by events, not by when a satellite will pass over on a clear day or when a plane can be scheduled.

Drones have shifted the economics of aerial imagery a bit, but only for those who are allowed to fly them. While the Federal Aviation Administration figures out how to get its act together on drones and allowing them to fly—probably no sooner than 2015—DIY aerial mappers don't face those kinds of restrictions. And balloons and kites have the advantage of being able to go just about anywhere on Earth, or at least anywhere that's not restricted airspace, without any runway requirements.

"UAVs are highly regulated, but these are systems you can use today, fly and start making maps, reusing materials you already have access to," Long told me as I was preparing to begin my own DIY mapping odyssey. "They're easy to use, and you can easily train others to use them."

With a regular point-and-shoot camera, the Public Lab design can be used to gather gigabytes of relatively high-resolution images that can be stitched together into a massively high-resolution image of the surface below. But add a smartphone and you get a lot more. Time-lapse photography and GPS location apps combined with a phone's cellular data connection can turn a balloon or kite into a real-time surveillance platform for the masses.

All those things make DIY aerial mapping an attractive tool for people and organizations beyond environmental scientists and the traditional cartographic community. Another reason do-it-yourself aerial photography is important is that mapping, like most of the "citizen science" Public Lab makes possible, can be a political act in itself. For some it's a way to counter government aerial surveillance—as one Palestinian activist in Jerusalem put it, "reclaiming the territory above our heads."

Activists have staged workshops worldwide on how to do "civil aerial mapping" as both a way of promoting government and corporate accountability and as a political statement. WeFab, a "maker" education collective in Milan, held such a workshop in May as part of a series of events at the Triennale Milan.

Dr. Ilaria Vanni, a professor at the University of Technology, Sydney, attended the workshop as part of research into the maker movement. She interviewed some of the organizers, including WeFab co-founder Zoe Romano, on behalf of Ars. "'If you look at the city of L'Aquila, destroyed by an earthquake four years ago and left in ruins, despite the Italian government's promises and despite mainstream information, producing an aerial map of the city as it is and publishing it is already a step to circulate correct information," Romano told her.

Here in the US, Long and others in the DIY mapping movement have used the tools to document political protests like those held by the Occupy movement. Long recalled one event in particular in May of 2011 where a balloon beat most forms of aerial surveillance—an Occupy event at University of California-Davis protesting the use of pepper spray against nonviolent protesters on campus. "It was foggy, and helicopters could only fly at 300 to 400 feet above ground. A satellite wouldn't have found the crowd under the clouds," Long recounted. But Long and three others floated a balloon up just below the clouds as the fog started to lift, providing a perfect aerial image of the event that helped capture the scope of the crowd. Organizers now had a tool to counter the campus administration's downplaying of the event's size.

Listing image by Ilaria Vanni

Listing image by Ilaria Vanni