"But I saw something else," she says. "I said, 'Oh, my God.' Lee saw so much more carnage on the second day of the battle, more than most historical accounts say. How might that have contributed to his well-documented illness that night? And the next day, when he ordered Pickett's Charge? It could make a whole new study of Lee's emotional state and help us understand how he could make such a terrible decision and send his men into the teeth of destruction."
The digital revolution has revolutionized maps, turning them into tools that tell of resources, history, and people.
That transformation shows how we have changed along with our maps. Once, we wanted to know only how to get there and what the land looked like. Now, we ask much more: What and who is nearby? Resources? History? What does it look like at eye level? Zoom in. Draw back. Move it around.
We even talk to our maps. And they to us. "Prepare to turn right." "Turn right." And, when we miss the turn, the faintly irritated (and irritating) "Recalculating."
Digital maps swivel to let us see various views of the same terrain, with accompanying information. Many handheld devices, such as the iPhone, offer geolocation apps that let you toggle among a traditional map, a satellite view, and a combination of the two, plus listed directions.
At the far edge of the new mapmaking is "augmented reality," remarkable 3-D rolling views at eye level of where you are or where you want to be. Bing Maps has Streetside; Google Maps has Street View. You can see your house from here, rotate it, see what's around, get down on the street and take a look. And look: lists of nearby restaurants, shops, services.
That's not to say paper is dead. Says Tom Harrison, a respected maker of hikers' maps in San Rafael, Calif.: "My customers all have digital somethings, but they all want their foldable, waterproof maps, too, which are still more practical than the small handheld devices. My customers want to know, one, how far is it? Two, where does it go? And, three, is it up or down?"
Harrison is no enemy of digital. He simply wishes it were done better. "Frankly, much of what you're seeing is downloaded off the Web without much thought and simply digitized. I want something more thoughtful. People see a gold rush in digital maps and are slapping things together without proper consideration."
Amy Hillier, assistant professor of city and regional planning at the University of Pennsylvania's School of Design, is no enemy of paper. "I am very fond of the maps created before the digital age that have an elegance and artistry that GIS can't generate," she says.
But Hillier, who maps cities in terms of social issues, knows the power of the new technology. She mapped residential mortgages issued in Philadelphia during the 1940s and 1950s. That showed how and why lenders gave or refused mortgages in the now-illegal practice known as "redlining." That told a story of racial discrimination and a city's ills.
"The best maps also make an argument about how the world is," Hillier says. "They can allow us to bear witness to injustice and disparity."
And to human limits. "Google Earth is great," Knowles says, "until you get over to Africa, where it maybe isn't as complete and doesn't look as real. There are gaps in the information. All these technological images are still human constructions subject to our limitations. It's easy to be fooled into thinking we're always seeing the real thing. Every mapmaker selects where the map will speak and where it will stay silent."
The more we ask of our maps and the more they can tell us, the greater the moral burden. Hillier describes her ideal map: "I'd like to be able to map grief in Philadelphia." Easy enough to make a map showing where people - primarily young black men - have been shot and killed. But she dreams of "a map showing the network of grief that comes from every one of these losses. What is the ripple of pain that passes through a community? Could the map be made to show where grief is heavy, where mothers constantly fear for the well-being of their children, and where life is more carefree, where no one gives a second thought to playing outside or walking to the store after dark?"
The answer: Yes. Today, that map could be made.
Contact staff writer John Timpane at 215-854-4406, firstname.lastname@example.org, or @jtimpane on Twitter.