It’s no secret that Niantic uses the Google Maps engine to power their map system for Pokemon GO. Now there are reports of players with a more up to date map. But what does this mean for you, the player?
Whenever the Pokemon GO map changes, more than just the cosmetics change with it. The appearance and frequency of certain Pokemon are very much influenced by the geographical details they reside in. For example, Water Type Pokemon are more likely to spawn near lakes, ponds, and rivers. Any newly added bodies of water mean more Water Type Pokemon are due to appear. Designated park zones are another critical aspect of the map. Places considered (and marked out as) a public park have naturally higher spawn rates than other locations, presumably to encourage players walk in public parks and not in the streets.
If you’ve ever said “I have a pond right here, I should be getting more Goldeen” then you might want to check that area again. Your fish driven desires may have become reality.
Update: This is not a newer version of the Google Maps engine. Closer observation reveals that this is actually a new map engine entirely. Niantic has retired the Google Maps engine in favor for OpenStreetMap, an open source map system. Expect more changes than just lakes.