For access points you can use either method.
It is more a question of how you would like them presented to you.
For example, if you create a network per geo-graphic location, your client view will be separated by geo-graphical region. For example, if you want to know the top talker by region this is perfect.
If you are only interested in overall information then one network for all the AP's might be better. Then results like top talkers will be shown across every geo-graphic location.