Right, I just played around with Google Earth for a while, and did some more organized research about the locations in Yokohama Kaidashi Kikou. The first draft of the results can be found here:
http://wakaba.c3.cx/ykk/ykk.kmz
You can either load that up in Google Maps, or you can use my new toy, an online KML/KMZ file viewer using the Google Maps API:
http://beta.4-ch.net/kmlview/kmlview.pl?url=http%3A%2F%2Fwakaba.c3.cx%2Fykk%2Fykk.kmz
This covers what I could figure out from volumes 1-10. Many entries are somewhat uncertain, and are marked with (approx) for locations that I only know roughly where they are, and (wild guess) or (?) when I'm just guessing from insufficient clues and/or intuition. There are probably more locations that can be identified from the first ten volumes, so if you have a copies of YKK and Google Earth handy, and feel obsessive enough, feel free to make corrections and additions! I'll be working through the later chapters at some point, too.
Unsolved questions and mysteries:
- Where exactly is Café Alpha? I've got a guess that I think is very good (especially if you compare the high-res footage available only in Google Earth with the big view here: http://ykk.misago.org/Volume1/26-27), but I am not entirely sure yet.
- And where exactly is the viewing spot that people like to go to watch submerged Yokosuka? It appears in several chapters, starting with 22 - Yokosuka Cruise. I've got the rough position for that, too, but it'd be nice to know the exact spot. It probably exists today in some form.
- Where does Alpha go to fire her gun in chapter 95 - Green? The sign implies that it is a US military area (there's a big navy base in Yokosuka), and the backgrounds show some barracks and a tower that seem to imply that Ashinano has some specific location in mind, but I can't figure it out from just those clues.
- Where is the Sandy Beach that appears in a lot of chapters, starting with 14? I've got a guess, but it's pretty uncertain.
- And of course all the other locations marked as guesses are also unsolved mysteries, plus the locations I didn't even bother to try and place.