I'm not sure who I'm replying to here, but I'd like to add a few use cases here (informally, of course). As a former law librarian, the notion of geographic 'coverage' that isn't explicitly of a subject nature is pretty common. Jurisdiction is one such thing, and the kinds of laws that get passed by one jurisdiction applying only to a subset of the geographic area that is the jurisdiction is another.
So for instance, the illinois legislature passes a law that applies only to a specific state resource, say the waterfront along Lake Michigan. You have two geographic instances here that are not necessarily subjects. The law is not 'about' Illinois, nor is it really 'about' the Lake Michigan waterfront. I know that many will protest this as similar to Karen's 'map of San Francisco', and it is in some respects. However, I happen to think that no bytes are harmed if we do both, and for the legal beagles, the 'applies' to idea exemplified by 'coverage' is pretty important.
