Every single guy or girl knows the feeling: You get dressed up to go out, hoping to meet someone. And then you get to the bar. And it's just filled with other girls/dudes. Your night busts out, or it never quite recovers from the buzzkill.
Finally, there's a solution: WeePlaces, a info viz startup we've covered before, has used Foursquare data to figure out exactly what places in SF and NYC have the best girl/guy ratios (and vice versa). The resulting interactive chart, called Ratio Finder, has just been made available to all.
The real lesson of it is probably known to pick-up artists from around the world. Girls cluster around cafes, shopping, and parks. Guys like bars. Take New York, for example:
Ergo, if you're a guy, you should zone in on pick-up spots by the light of day, if you'd like to have your pick among more ladies. Likewise, if you're a girl on the prowl, nightlife favors you. Moreover, the old adage about SF having far more men than women, and NYC having far more women than men, seems true.
Compare, for example, check-ins at nightlife spots (one of the many sorts of venues you can refine the maps by). In San Francisco, bars, on average, have 14% more men:
Buy in NYC, the ratios are far more balanced, with about 2% more men than women:
Words obviously can't do this justice -- check it out yourself.