I've got a Nuvi 550 with the street map installed. Can I install topo maps from this site without interfereing with the original street map and switch between them on the 550?
Yes.
I've finally downloaded the S.E. United States Topo Maps with Installer. Do I need to use the Map Source Tool to install these maps in my 550?
No. Run the .exe file. It will intall the mapset to MapSource. In MapSource select what you wish to load to the GPSr.
See: http://www.gpsfiledepot.com/tutorials/how-to-load-maps-on-my-garmin-gps-unit/
I've got the maps in MapSource. But when I try to put tthem into the 550, I get a window that tells me that the maps are 934 mb and there's only 642 mb available. "Please select fewer maps and try again." However, I put a 4 gb Micro SD card in the 550. It should have plenty of memory.
The problem is, you must select the memory card in mapsource. If you're getting that error, you have chosen the Nuvi's internal memory instead.
On "My Computer", it showed drives F, G and H. G drive was marked as Garmin. The Micro SD card was actually the H drive. Surprise, surprise! Thanks for your help.
Yeah. I solved that problem by renaming the SD card as 500SD (for my 500). That solved the problem of seeing it.