Maybe, to start with, merge the "on a" and "in a".
Again, too general and not very helpful. Have you had a chance to look at them and give more specific advice?
I am happy to merge locations that are obviously duplicates eg *exactly* the same in regards to wording and spelling. But all the "on a" and "in a" locations are different. Some of these may actually represent the same place but many are clearly different places. It would not be practical to lump them all together.
I need to know *exactly* which zone to combine with each zone. If you give me a detailed list, that would be great.