> Therefore, how can I download a new map into my GPS without erasing
the
> other maps in the GPS?
You can't. The Vista wipes out all maps except the base map whenever you
load new ones. You'll have to reload them every time. If you're trying
to save space, in the Vista it may not be a problem (though it may be a
bigger issue for topo maps than it is for my roads & rec maps). But
timewise, you just have to live with it.
Right now in my Vista I have the entire state of Arizona (Roads and
Rec), plus every county that I-10 goes through in New Mexico and Texas
as far as Dallas. And it still says I'm only using 13% of available
memory. Depending on how many different places you're traveling, you may
not have to reload your maps that often.
Steve
Team Tierra Buena