I read on the web where it comes preloaded with a North America map. I'm waiting to see how much detail the map has. But, on my old eTrex 30, I also use some of the maps here, especially the Yosemite map with all of the trails and features. The Garmin manual describes a procedure where I can load additional maps from their website. Are the maps here compatible with the new unit? Is there a way I can load them on my device?