This site uses cookies to offer you a better browsing experience. Find out more about how to manage cookies, or dismiss this message and continue to use cookies.

eTrex and map questions

I’ve been using - with satisfaction - an eTrex 10, and I want to get a 20 or 30, so that I can have “real” maps. Either will do; they have practically identical specs.
I have a few questions:
1. Have the 20 and 30 been around long - so that they are do for a “replacement”? Or are they old standbys in the Garmin line-up that will continue to be current? Any guesses?
2. I have been doing some research, and see that I don’t have to purchase Garmin’s City Navigator maps; there are free OSM maps. Is the quality comparable to Garmin’s maps?
3. I would be putting additional maps on an SD card I guess; can more than one map be placed on a card? And if more than one, how does one choose which map is “active”? Even if only one, does the SD card map replace the pre-installed base-map automatically?
4. Can I place a map (or maps) in the internal storage? There's 1.7 GB internal memory. If so, how is that done?
5. Is the 20/30 fast enough to deal with a map with a TYP file? Or should I download the plain-vanilla map?
6. I use Mac. There seems to be 2 ways to get an OSM map on the card: an “installation”, and a simple copying. Is there an advantage to doing one? Which one is preferable? Do I have a choice if I want to put more than one map on the card/internal memory?

Thanks for the advice.


  • Boyd 1985 Points
    1. Not very long. They were Garmin's first devices to use the GLONASS system. The only other handheld with this is the just-released Oregon 6x0 series.

    2. OSM is created by user contributions and may or may not be as accurate as the Navteq data in City Navigator. It will not have the rich POI database and has limited routing capabilities. Also lacks lane assist, speed limits and junction view but I don't think the eTrex supports any of these anyway.

    3. You can store many maps on the card, not sure of the exact limit but I believe it's more than 30. You choose the map from a setup menu on the eTrex.

    4. Yes, works the same either way. Basecamp/MapInstall are usually used to send maps but some are available pre-compiled and can simply be dragged/dropped to the Garmin folder.

    5, A .typ file should not have any impact on performance. The complexity level of the map itself can affect performance. The eTrex has been criticized for slow screen updates when using raster imagery, like satellite photos and scanned topo maps. But these have nothing to do with .typ files.

    6. I don't use OSM, but I believe the difference is that the "installation" allows you to use the map on your computer for planning in Basecamp. Basecamp can directly access some (but not all) maps when the GPS is connected, but installing directly on the computer is more convenient and gives better performance. To use precompiled maps, just be sure they have unique file names and an .img extension, then place them in the Garmin folder.
  • sussamb 813 Points
    Boyd's comprehensive reply has pretty much covered all the bases. I have an Etrex 20 and have numerous maps installed, both OSM and Garmin's City Navigator maps. You can select more than map should you wish, and set up profiles as you want them ... so I have various profiles including one for walking and a different one for use in my car, each profile uses different maps. The basemap BTW remains on your Etrex, it's not overwritten by maps you load yourself.

    If you haven't already discovered them there are good sites for maps in Europe here:

    and here:
  • Ramaprem 112 Points
    Thanks so much for your quick and very comprehensive replies.
    I'll be ordering the new Garmin pronto; your replies make it clear that it will do what I wish.

    Regarding that:
    I have a Garmin nuvi for car navigation - so the eTrex would be for walking/hiking/cycling. I don't need sophisticated (car-type) navigation for that activity; the eTrex software will do. I just want to see where I am, and what is around me. Following a track in reverse - or being pointed to a waypoint - is all that I need.
    I assume that my track be shown on an OSM map; correct?

    I'm also not interested in merging computer with eTrex; I simply want to take the eTrex with me at times when I am visiting an unfamiliar city, for example. So does that mean that I can forget BaseCamp and installers? And just download the image file and drag-and-drop that file onto the card - after creating a folder "Garmin"?
    If so, can I do whatever with the card while it is in the eTrex? The eTrex card will appear as a mounted volume in Finder? The eTrex becomes a card reader, correct?
    And can I simply change the name of a map - in order to place several maps on the card? So maps - on my card - could be named,, etc.?

    And, is there a size limit of card that the 20/30 can deal with?
  • sussamb 813 Points
    If you set your track to be shown it'll be shown whether you have a map installed or not.

    Basecamp isn't necessary at all to do what you want, but it is useful for planning routes, trips etc so it's something you may wish to think about. When visiting foreign cities for example I plot all the places I want to visit on my PC using Basecamp, then download them all in one go to my Etrex.

    As for cards etc. Your Etrex will take a card up to 32Gb, and yes, you can rename the map files to what you like and they'll work as long as they are in the Garmin folder, either on the Etrex or on the card.

    Both the Etrex and card show as separate volumes when connected to your PC.
  • Ramaprem 112 Points
    Very clear info. And much appreciated, again.
  • Ramaprem 112 Points
    I've been downloading maps of Germany and Switzerland in anticipation of the arrival, in 2 days, of an eTrex 20. What I've been downloading are the maps which can be copied to an sd card - not installers which use computer software.

    I've gone to the two sites mentioned in an above post. I've downloaded 4 maps: 2 of Germany, and 2 of Switzerland.
    From the "Freizeit" site, I got 2 .img files (after opening the zipped file); from the .nl site, I got one such .img file, and one .gmap file.

    Does this make sense? The .img files cannot be opened; they aren't disk images as I know an .img file is.
    Are all 4 of these files valid maps, that can be copied to the sd card, and recognized by the eTrex?

    If so, is there a difference between the 2 file types? Is one preferable?
  • sussamb 813 Points
    You need to use the .img files and they should be placed in the Garmin folder on the card .
  • Boyd 1985 Points
    The gmap files cannot be directly used on the GPS, they are used by Basecamp on your computer. But it's a little hard to say more without knowing what you have. Does it have an extension of .gmapi or just .gmap?

    On the Mac, if you have properly installed Basecamp it will also have installed another program called MapManager.

    Normally you get a .gmapi file, which behaves like an "installer" when double-clicked on the Mac, starts the MapManager and asks if you want to install the map.

    With a .gmap file however you *should* be able to just move it to the following directory (where "YourName" is your user account on the Mac). Note that new versions of MacOSX hide the Library directory, but there are various ways to access it

    /Users/YourName/Library/Application Support/Garmin/Maps/

    Quit from Basecamp if it's running and restart it, then hopefully you'll see the map. It can then be installed on your GPS in the usual way with MapInstall.
  • Ramaprem 112 Points
    As I wrote, earlier and just now, I'm not dealing with BaseCamp - and am not downloading files/installers that have anything to do with computer-eTrex communication. This doesn't interest me.

    I just want the map, and the map only - to be copied to the sd card inserted in the eTrex (when it arrives).

    Hopefully, sussamb's info is correct: the .img file is, basically, the map which will be recognized by the eTrex. And that the .gmap file is of no use to me - although, of course, I don't know how/why it arrived.
  • Boyd 1985 Points
    As I said, I don't know what you have, and it sounded like you weren't sure either. Some maps are only be distributed in a form that requires Basecamp/MapInstall. In my own experience, this form of map is by far the most common since it is more compatible with older devices and most people consider it preferable to have the map on their computer.

    But if you can find all your maps in the form that goes directly on the GPS, then you're good to go.
  • sussamb 813 Points

    I just want the map, and the map only - to be copied to the sd card inserted in the eTrex (when it arrives).

    Hopefully, sussamb's info is correct: the .img file is, basically, the map which will be recognized by the eTrex. And that the .gmap file is of no use to me - although, of course, I don't know how/why it arrived.

    I've used files from that site. You'll be fine just copying the .img files.
  • Ramaprem 112 Points
    Best news I've had all day. Thanks Boyd and sussamb.
Sign In or Register to comment.
↑ Top