Here’s the full map. The city is divided in two parts, and one is unlocked via the story, pretty much like in inFAMOUS. It’s been pieced together from several screenshots posted by Reddit user Redboiipod, as it’s impossible to zoom out and one screenshot didn’t fit the whole thing.
Under the map you can also see two in-game screenshots of both islands (one is a peninsula, to be more precise), as seen by one of the tallest skyscrapers. Some areas of the screenshots have been blurred to avoid power-related spoilers.