This looks great! How big did you have it printed? I feel like anyone working on the Batman comics should have one of these on their wall.
Is there a pattern to the numbering of the 22 locations? I found it very difficult to find the numbered locations, since there doesn't seem to be a geographic correspondence between the numbers and their location. I would recommend sorting the reference list by region/district and having the numbering within each region be consistent, e.g. southeast to northwest. If you find a number on the map, it's trivial to look up what it is, but it's just as common (if not more so) to go from the list to the map, and it's important to make it easy to find each place.
Another option would be to have multiple lists instead of just one, for example a list of landmarks (Wayne Tower, the Clocktower, the Botannical Garden, the Natural History museum, etc), a list of municipal structures (the prison, police HQ, etc), and a list of other places of note (Gordon's house, Wayne Manor, etc), so there would be no need for by-district organization, but the numbers should still have a rough geographical correspondence. I think this second option would be best if there were more numbered places though, perhaps 50+.