A map is a bird’s-eye view of the land—literally a top-down snapshot. For most of history, maps were socially top-down, as well. Cartography was an expensive, difficult endeavor, so only large, powerful agencies, such as national governments, could undertake the mapping of a country.
Now, however, private citizens can make maps of anything they like using online tools. In Santa Barbara, California, people map the wildfires that dot the land and threaten houses every autumn. In Brooklyn, New York, residents are charting which food stores carry fresh produce and which don’t. In Nairobi, Kenya, young Kenyans are working with a U.K.-based open-source cartography team to map Kibera, a large, previously unmapped slum. Kibera residents can access the map at internet cafes, says Eric Brelsford, a 27-year-old freelance computer programmer who has worked on the Brooklyn and Kibera maps. Volunteers have also been printing and handing out paper copies of the map, he adds.
The revolution in citizen mapping can be traced back to July 2004, which saw the launch of OpenStreetMap, the free online map that’s being used in Kibera. Anybody can edit OpenStreetMap—think of it as the Wikipedia of maps. In 2005, developers at Google Maps published their application programming interface, which allows people to create applications on top of theirs. The application TaxiWiz, for example, tabulates exact cab fares using Google Maps’ calculations for the taxi’s route and distance.
“And then it’s slowly taken off from there,” says Michael Goodchild, a geographer at the University of California, Santa Barbara, who studies citizen cartography.
If officially-made maps show what the world looks like from above, then citizen maps give a glimpse of how the world looks to the people on the ground. Each of these maps reflects its makers’ most urgent preoccupations, from “Is the fire spreading to my neighborhood?” to “Where can I find running water?” They record a level of detail that’s unaffordable for even large government agencies. And they fill in cartographic gaps that arise in poorer areas, like Kibera or Port-au-Prince, Haiti.
Generally, richer countries are better mapped, says Matthew Knutzen, a specialty librarian who curates the New York Public Library’s vast map collection. More affluent nations have more money to spend on cartography, while popular tourist destinations get mapped by private companies. Known as the poorest country in the Western hemisphere, Haiti has neither flush government funds nor tourist allure. The New York Public Library has hundreds of thousands of maps, but “next to no tourist maps of Haiti,” says Knutzen. In January 2010, when Haiti was hit by a devastating earthquake, OpenStreetMap volunteer contributors created the first-ever digital street map of Port-au-Prince so aid workers would know what roads were open.
Anyone who might have expected self-centered navel-gazing—something along the lines of, say, the first wave of blogs—will be pleasantly disappointed. Citizen cartography projects seem to grow out of urgent community needs and the cartographers themselves practically glow with optimism. “We’re going to make a map ourselves and anyone can help out,” says Brelsford. “Anything can emerge that you can think of.”
But how useful are these maps really? Professional geographers’ greatest concern is the accuracy of amateur maps. No one has done a study to quantify how accurate they are. It stands to reason, however, that with less expertise and less transparency in authorship, publicly-made maps are more vulnerable to inaccuracy than professional ones, says Matthew Zook, a geographer at the University of Kentucky.
Yet some of citizen mapping’s biggest hits have been very successful. Built in about three weeks, the January 2010 Port-au-Prince map “vastly outstripped” anything else available, says Zook. “It was extremely accurate and very useful for rescue and aid workers.” No official agency could have gotten a map out so quickly, he adds.
Knutzen, New York Public Library’s geospatial librarian, believes accuracy will only get better with time. Like many experts watching the citizen mapping trend, he likens its rise to Wikipedia’s trajectory over the past decade. As with the crowd-created encyclopedia, he says, more contributors will improve public maps’ content. “It’s become very difficult to tell the difference between quote-unquote professionals and amateurs.”
Once that line blurs, what will happen to the idiom about putting something on the map? It used to be that you had to catch the attention of the big guns to get cartographic recognition. Now all you need is a cell phone. One non-profit platform, Ushahidi, allows people to text in information, which Ushahidi then collects and places on an OpenStreetMap. Ushahidi was founded to map reports of violence after the 2008 Kenyan election and it’s since been used to show flood damage in Queensland, Australia, and crime reports in Atlanta, Georgia.
Looking down at the world from above will never be quite the same again. Maps have richer textures now, and finer details. They teem with information, and with the fears and worries of local residents.
They also allow locals a say in defining their homelands, says Brelsford, who remembers he decorated his childhood bedroom with pages taken from atlases. “There’s a lot of power in a map.”