The nice thing about Pokemon GO (Free) being built on various databases with available APIs is that it has inspired people to make their own tools to find Pokemon, to try and streamline the process. Pokevision is one of the most powerful tools yet – it allows you to scan the area near you for which Pokemon are available, and when they will despawn. This way, if everything is accurate, you can streamline your Pokemon hunting. As reported by Tech Insider, Pokevision uses Nantic’s API to help find this data.
Now, Pokevision isn’t 100% accurate for everyone. It might not necessarily show activity at all spawns near you. And lured/incensed Pokemon aren’t liable to pop up on the map, so it’s best to use this as a rough guide more than anything. As well, you do have to run the scanner every time you pull up a new location. But a rough guide is a better start than going in blind, so hopefully Pokevision helps you out.