Topics

Sorry for the long title and I hope this question is in the right part of the forum. 

GPSr: Oregon 450t

Question:  Despite the fact that this unit comes with preloaded topo maps, I'm going to want to add more maps in the future.  Specifically Michigan (Upper Peninsula) and Canada (Ontario).  I know that I can purchase 24k maps from Garmin or other sources by either getting a loaded micro SD card or by downloading the maps.  Now, would it be best to buy a new, clean micro SD card and use that one card as storage for all the custom maps I would like to create in the future or better to get the micro SD cards that are already loaded with the maps?  Also, as a follow up, if I create maps and save them to the SD card when I go back and add more maps do I have to upload everything all over again? 

I appreciate any input and if I'm in the wrong place just steer me in the right direction. 

Thanks