Thanks, all! Chippy, I'm subscribed to the mailing list already, though I have yet to get any messages. Would be fun to meet a few other people doing this!

FK270673: Thanks for the tips. Not sure it is directly applicable to city blocks since the third number is connected to individual buildings and those become kind of difficult to map with a GPS since the resolution simply isn't there (and owners may object to people running around their property with a tape measure). I have to find someplace on the map (Tokyo perhaps) where someone has already done this and look at exactly what they did, I think.

Street names are easy; most streets have no official designation at all. How do I add block names and numbers, though? It feels sort of wrong to add an area just to have something to attach the name to (not to mention having to move all abutting areas if you adjust the street). House numbers would go with the individual buildings of course. It would be good if you could somehow reuse the nodes defining street corners to delineate blocks.

I'll cross that bridge when I get to it; first I'll just try to get my current area streets mapped out.

Pretty much what I was thinking. Yahoo doesn't have decent coverage of Osaka (the aerial imagery doesn't even resolve to street level) so that is no guide. What I am mostly concerned about is the idea of basically tracing the sidewalk, not the street, then placing the street next to the trace. The accuracy won't be great, but it should be a lot better than not having the street at all?