You might’ve seen a few PokemonGo APIs released recently, covered on Verge and Polygon. People have been building tools for finding what Pokemon are near you right now — I decided to take make a map of the available data to figure out the game’s behavior.

I’ve only taken a look around part of the Bay Area for now:

San Francisco

My current theory is that certain locations are set to spawn certain sets of Pokemon, making them destinations to either acquire or train that species. Many players are already aware of this behavior, calling them “spawns” or “nests”.

Distribution of Bulbasaurs in San Francisco

Presidio was rumored to have a large number of Bulbasaurs

If you’re trying to get Magikarps for a Gyarados:

Magikarp concentration

Some observations of note are that Pokemon don’t appear to spawn in airports or in most hospitals, which makes sense for a variety of safety reasons.

Left (Pidgey) Right (Zubat) distribution

Left (Pidgey) Right (Zubat) distribution

Let me know any questions you have or things I should further investigate! This is part 1 of a series of posts I’ll be making.