For example, I have a set of 1300 MetroGuide and Topo maps that cover much of the western US and take up about 470 MB of space. While not a big deal for the default 64 MB microSD card that comes with most of these units, filling up a 512 MB card using USB 1.1 can be time-consuming. Maximum transfer speed for a standard microSD card is on the order of 80 Mbps, well below USB 1.1’s speed. It appears as though the USB connection used for uploading map data is USB 1.1 at 12 Mbps, not USB 2.0 at 480 Mbps. But there are two drawbacks to these large-capacity microSD cards:ġ.
Added : Recent hardware upgrades to some Garmin units may have increased this to 4 GB, but there are apparently issues with some cards. I’ve seen 1 GB microSD cards for less than 15 dollars, and Garmin says that their units will support 2 GB cards (but not SanDisk Ultra II cards). And the microSD (aka TransFlash) memory cards allow for lots of room for Garmin’s uploadable maps, like the Garmin USA Topo or City Navigator series. While not geodetic-quality, if you use any of the SirfStarIII units with some care it’s possible to achieve 1-2 meter real-time positional accuracy repeatably. The HCx models also use the SirfStar III chipset. The first four are very similar in their electronics and capabilities I own the first on the list (the 60Cx), and it’s fantastic! The SirfStarIII chipset allows fast position acquisition with incredible sensitivity – I can get fixes in heavy tree cover and mountainous terrain that gave my old Garmin eMap fits. Among the models with this capability are: The new Garmin handheld GPS units with the “x” designation now offer removable microSD cards for map storage.
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