[ gpsdrive ] Canada/US Street Map Download

[Tux]

I'm sure you guys get this question relatively frequently, so apologies 
for my clueless noobness. I have Googled but didn't find the one-step 
answer I'm looking for. I hope someone can help me.

Basically, I need to know the command or list of commands that will 
download all the street maps for Canada and the US at a scale useful for 
navigtion while driving. Disk space isn't an issue.

I hope someone will get back to me! Thanks for your indulgence.

Glyn