Citymap for online game

We are working on a online game where the Players have to talk a walk through a City. The have to stop a each Highlight of the City and answer a question in order to move on in the game. For that we Need a Partner how can make us mapes for different cities which we can use for our game. We will let u know more later and give u an example of what me mean by that. The Job could lead to a Long partnership because we are planning on making the game in many cities - so we are going to Need new City maps all the time.