The virtual world has never been more connected to the real one. Satellite imagery and geography markup language are all over the Web, and GPS receivers come built into cell phones and other everyday gadgets. All the overlords of Internet search – Google, MSN, Yahoo!, even Amazon’s A9.com – provide cartographic results embedded with information. Augmented reality is the latest benchmark of the digital age.

How did we get here? This technology used to be top-secret government stuff. Then, in the 1980s, McDonald’s dumped thousands into buying satellite images and developing software called Quintillion, which predicted the growth of cities and school districts. Ever notice there’s always a McDonald’s where you’d expect one? The company looked down from the heavens and dropped new franchises wherever it saw the right combination of kids, interstates, and suburbs, using one of the first geographic information systems for business analysis.

In 2005, anyone can have a god’s-eye view. MapQuest began doing rudimentary online maps in 1996. Google acquired digital 3-D mapmaker Keyhole in 2004, and with the resulting Google Earth, explorers are able to find the nearest dry cleaner or tapas joint anywhere on the planet, a capacity that corporate advertisers are bound to exploit.

But maybe that’s not what maps are for. At their best, they’re user interfaces to the world, connecting places and people. Google has figured this out – the company knows its maps are only as good as the refinements made by users. In June, it gave away the code to its maps, as did Yahoo! Now an army of amateurs is flooding the Web with map-based analyses. ChicagoCrime.org lets users evaluate Windy City neighborhoods based on police data. Gmaps Pedometer lays out distances between any two points. And Squid Labs is working on augmented-reality screens that embed tags into 3-D space so you can tour a museum or battlefield and readily footnote what you see. And what’s more brilliant than those open source subway maps optimized for an iPod screen?

On the other hand, the most powerful maps can actually make it easier to get lost. Dazzled by their features – immersed in topographic information and GPS coordinates – we forget just to look around. In his book Between Meals: An Appetite for Paris, A. J. Liebling blamed a decline in French cuisine, starting in the 1920s, on the Michelin Guide. Prior to its publication, he argued, anyone brave enough to open a restaurant had to face the scrutiny of repeat customers. With the advent of this book, however, day-trippers would blithely follow its recommendations – once, and they’d never return. The fact that you can now download Michelin’s Paris guide to a PDA would probably have horrified Liebling. ChicagoCrime.org should worry any urban planner looking to revitalize a historic district. That’s the SimCity trap, emphasizing spatial relationships over more intimate, human considerations.

But hey, hook us up with a restaurant-review site that combines local maps with the scrutiny of, say, Chowhound, and Liebling will rest easy in his grave.