I HAD the route mapped out in my mind. I would bike from the Lower East Side of Manhattan, hit the taco trucks along the ball fields of Red Hook, Brooklyn, cruise through Prospect Park over to Brighton Beach for a quick dip, then hypotenuse it back to a bar in Williamsburg to watch the World Cup finals.

Out of curiosity, I consulted Google Maps’s new bike software on my computer, to see if its brainy algorithm would match my battle-tested sense of directions. It did, for the most part, but for a few snags: It sent me the wrong way on Smith Street in Brooklyn, then diverted me away from Prospect Park  the borough’s best piece of biking real estate  and on the way back, like an overprotective concierge, it steered me away from the rough parts of Bedford Stuyvesant (normally I would have just bombed up Bedford Avenue).

Still, not bad for a piece of software created by some techie thousands of miles away.

“It’s still an experiment of sorts,” said Dave Barth, a product manager at Google Maps in Seattle. “We launched the bike maps without complete coverage because of the passion we were hearing among cyclists on the Internet.”

The beta version for bicyclists is just a few months old, but it is already reshaping how bike enthusiasts travel. Spanning more than 200 cities nationwide  and with plans to roll out bicycle routes internationally  Google Maps relies on a mash-up of data, from publicly available sources like bike maps to user-generated information. It joins a host of other bike-mapping Web sites, from Bikely, which lets people share routes in cities around the world, to Ride the City, a geowiki (or self-editing map) app, available in 10 cities (including New York, Boston, San Francisco and Toronto) that allows users to edit their routes as they ride, to MapMyRide, which is geared more toward fitness training and logging workouts.