Online Trick

A quick geo-tip:
With the osmar and maptools package you can easily pull an OpenStreetMap object and convert it to KML, like below (thanks to adibender helping out on SO). I found the relation ID by googling for it (www.google.at/search?q=openstreetmap+relation+innsbruck).

# get OSM data
library(osmar)
library(maptools)
 
innsbruck <- get_osm(relation(113642), full = T)
sp_innsbruck <- as_sp(innsbruck, what = "lines")
 
# convert to KML
for( i in seq_along(sp_innsbruck) ) {
      kmlLine(sp_innsbruck@lines[[i]], kmlfile = "innsbruck.kml",
               lwd = 3, col = "blue", name = "Innsbruck") 
      }
 
shell.exec("innsbruck.kml")

This is a handy option for displaying Google Maps in Google Earth. This could be any of your own maps created in Google Maps, a route or whatever. One nice feature of GE's Network-Links is that if you or any other contributor of a Google map modifies it (in Google Maps), it will be refreshed also in Google Earth.To do so, just grab the link from Google Maps. Like this one for a route:

https://maps.google.at/maps?saddr=Tivoli+Stadion+Tirol,+Innsbruck&daddr=Haggen,+Sankt+Sigmund+im+Sellrain&hl=de&ll=47.227496,11.250687&spn=0.12007,0.338173&sll=47.230526,11.250825&sspn=0.120063,0.338173&geocode=FagR0QIdYR-uACGQHB8W0fIkjCkfsEUhQ2mdRzGQHB8W0fIkjA%3BFZhY0AId6CypACnvxXqyRz2dRzG6da9r3hgbNA&oq=hagge&t=h&dirflg=h&mra=ls&z=12


Then go to GE and choose "Add" from main menu and "Network-Link" from the submenu. Then paste the above link and append "&output=kml" to it. That's it!