If you have several MapSource discs, open them all at least once. Your mapsource program will add each disc opened to this list.
You want all of the MapSource CDs you own to show up on this list because sometimes you will want to load some "Roads and Rec" zones and some "US Topo" zones and maybe a "Metroguide" zone onto one datacard. To do so you must choose all the zones within one session. You will need to have every disc (chosen within one session) with you because MapSource needs the disc to build the map set. Every time MapSource loads map zones, it erases the current map memory in your GPS or datacard.
For example if you have an 8Mb datacard, you may want to put in one 7.5Mb Metroguide zone, then fill up the rest of the .5Mb of space with Roads & Rec zones (usually .2Mb to .3Mb each).
The Highway basemap in your GPS is not eraseable or updateable.
A. To start, choose the "zone tool"
B. The pink area shows a zone chosen. This shows up in the list of maps to the left.
C. The yellow outline shows a zone outline and below you can see the memory allotment required to add this zone.
A. This area shows the cumulative size of the chosen map set. If you have a III+ or 12MAP then the max is 1.4Mb. If you have a datacard, then the max is somewhere near the datacard size (8Mb, 16Mb, 32Mb, 64Mb, 128Mb etc). We have put 8132Kb into an 8Mb datacard so in some cases you can go slightly over.
B,C. The pink area shows zones chosen. This shows up in the list of maps to the left.
D. When you are done choosing zones, poke the "load to GPS" button (little GPS wth the blue 'down' arrow directly above the map zone tool).