Last year I bookmarked my favorite running trail (over 4,000 times)
in the San Jose area on google maps.
http://maps.google.com/maps?q=Stanford,CA&ll=37.408522,-122.178805&spn=0.005504,0.008304&t=k&hl=en
When I reviewed this bookmark recently at maximum magnification I could
see individual runners
on the trail. The image was taken in late afternoon (shadows point
northeast) and the shadows
are about twice as long as the runners are tall, which helps
distinguish the runners.
I'm pretty sure its an satellite picture, because it seems to stay the
same when you go out
seven or so de-magnifications.
(One of these days I'll plot my favorite runs on one of these mapping
programs.
There are sotware utilities that draw lines on the maps if you give
them a set of lat-longs,
either from GPS waypoints or clicking the maps themselves.)