[colomon]

Ooo, I'll have to look into that. I had a fun couple of days a few years ago comparing Google Maps satellite images from St Clair County, MI with the old maps which showed where the Interurban ran. It was really impressive how much you could still see the routes from above, even though the tracks were torn up 80+ years ago...

[maxerickson]

The resolution can vary a lot. Michigan tends to have a lot of very nice data because NOAA has recently been doing scans of the Great Lake shorelines.