After many hours of experimentation using 2 sandisk micro sd cards (8gb and a 16gb) I have found my astro 320 will only recognize the last map added to the sd card. I can add one state topo map or 3 state topo maps per card and the only one that shows up on the map list except for the permanent world wide dem map. I cannot add a state topo and a transparent trail map for example since the only map that shows up is the last one added to the sd card. It is not a big deal as I can just have a bunch of cheap sd cards with the maps I want, but after 6 hrs I would like to know why the gps cannot recognize more than one map. I dont think it is exceeding the 4 gb limit I saw concerning Nuvis. Any ideas??? thanks
On that unit you can send one map, then rename the gmapsupp.img to something else such as example1.img
Then send a second map such as the trailmap and then rename that gmapsupp.img to example2.img
And so on, and so on...
They should then show up as separate entries and not overwrite each other.
I do not understand how to rename the maps as you describe. Do I change the name on the sd card? When I look at the sd card after loading several maps I only see one garmin file. Sorry I need instructions for a simpleton. thank s
You change the name on the SD card, as you would any file name on your computer. Rename your first gmapsupp.img to say Iowa.IMG. Send the next gmapsupp.IMG and rename it to NewHampshire.IMG. Sent the third one and rename it to HuntingGrounds.IMG.
The reason you only see a single gmapsupp.img is that it's always getting written over. If you change the name, it won't get written over, because MapSource/BaseCamp only writes to a single file name "gmapsupp.img".
I tried this suggestion and added a couple maps to the sd card. I changed each name as suggested and the astro did not recognize any of the maps ie none came up on the map list including the map that worked prior to changing the name. It appears to me: the astro only recognized the file when named garmin... and the file gets written over each time I add a new map??? Does this make sense?
I assumed from the Garmin site that since the Astro 320 resembled the GPSmap62 that it would permit the same multiple file naming system (described above by both me and Indrid Cold), but I didn't see any description of the file system on Garmin's Astro 320 pages. If that's not the case you should be able to combine multiple mapsets using MapSource or BaseCamp and send them to the Astro as a single gmapsupp.img. See the tutorials if you don't know how to do this.
What OS and mapviewers are you using? Have you updated to the latest firmware?
Amazing. I was having the exact same problem today, trying to load a map that I had made along with the Garmin Topo and both maps were put together in a single file so that you couldn't deselect them (which I _can_ do on my Legend).
But Indrid Cold and Seldom had it exactly right: download one map, change the file name, and download the next. You'll be able to select/deselect. Works on my Astro 320 just fine.
Thanks!
Newwood
If this isn't working you should run Garmin's WebUpdater to make sure you have the current Astro firmware loaded on your GPS.
FWIW, the Astro 220 will only accept 1 gmapsupp.img. When you rename the files you leave the IMG extension on them don't you?
I did use the .img extension when I renamed the files. I will try again since Newwood said it worked on his/her astro. My firmware was updated. Thanks to all for helping . I will let you know if it works.
Success!! One needs to open the gmapsupp.img file after loading each map onto the sd card and rename the files. Somehow I was not doing it correctly, but it works great now. Last question: do I need to disable maps I m not using ie will it slow down the gps or can I just leave them all on?? Thanks again for all the help.
Glad it worked. Regarding disabling maps. I doubt it will slow things down much if everything's enabled, but why don't you try it both ways and report back. Seems to me the only time you might run into a problem with processing speed would be when the unit was doing a lot of re-draws.
so how do you like your astro, are you tracking dogs with it? I really like knowing where mine are at when we walk at the club.
Some of the features aren't well documented but I have it figured out pretty good now. I have noticed mine "flips" more than my oregon, which is wierd. Sometimes it takes me more than once to calibrate the compass. Overall I like it though.