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Better to download or buy Micro SD?

Hello all.
Newb here and to GPS in general. I just bought a Montana 600. I'm looking to buy the Birdseye as well as City Navigator NA. Garmin offers the card or a download. I'm in no hurry so I don't need the the download asap. Which method would be the better option? Would the CN NA download take up too much space on the 600?


  • Boyd 1960 Points
    Lots of things to consider. Do you need Alaska or Canada? If not then the cheapest option is City Navigator "Lower 49" at $60. It is only available via download and is about 1.2GB. This is what I have on my own Montana 600.

    With any of the download products, you must install the entire map whereas the DVD version will let you choose a smaller area (not much reason for this on a modern device with plenty of memory though).

    The DVD version is installed directly on your hard drive and you use Basecamp/Mapinstall to send it to your GPS. The download or card versions are not installed on the computer, so you need to either connect the GPS or copy the map to a USB flash drive if you want to use it in Basecamp.

    The download and DVD versions will become permanently locked to your GPS and won't work on another unit. You can backup the map files to another card however, and the backups will work in your GPS.

    The preloaded card can be used in any GPS, it is not locked to your specific unit. Would be an advantage if you have more than one unit or if you want to sell the card later. But it uses hardware copy protection, so if you copy the map to another card it won't work. But also consider that the preloaded card ties us the slot in your GPS and you cannot add additional files. This might be a problem if you want to have a lot of birdseye on the unit, since you would have to put that in limited internal memory.

    Finally, with the DVD version you get the same "nuMaps" guarantee as the Nuvi series. If a new map comes out in 3 months you can download it. The DVD version is also eligible for lifetime or onetime updates, although they must be purchased separately. The download and pre-loaded cards cannot be updated and must be replaced if you want a newer map version.

    BTW, be sure to register your Montana. You will get a 10% coupon back that can be applied to either City Navigator or Birdseye.

    BTW - This question is often asked, so I'm turning your thread into a "sticky" :)
  • Thanks Boyd. I registered it and got the discount.
    I don't need Alaska or Canada so the lower 49 would probably be my best bet.
    I only have this unit at this time. No plans for a second but that could always change.
    As far as Birdseye memory, I'll be using it mostly for my hunting areas in CT. Probably about 6 or so areas in total right now. Not sure how much memory that use up.
  • One other thing, where did you find the CN Lower 49? I don't see it listed on the Garmin site.
  • Boyd 1960 Points
    It is here:

    For Birdseye, my "back of the napkin" calculation was that the highest quality imagery requires about 2.5 MB storage per square mile, so you can do the math on that yourself.

    One line of thinking is that internal memory is limited to 4 GB but you could put a 32 GB card in the slot if you wanted. So tying up the slot with a 1.4GB card containing City Navigator is somewhat limiting.

    But my own experience with a class 10 16GB card full of Birdseye was that it caused the unit to start up really slowly. So I only load small amounts of Birdseye on my Montana at a time to avoid that.

    You may very well be fine with nothing but the built-in 4GB. Personally, my card slot is empty right now. :)
  • I got the topo 100k on a scan disk in a bundle with my etrex 30. Is there any way to copy this to the hard drive of the pc for faster refresh rates?
  • Boyd 1960 Points
    What is a scan disk? Do you mean a micro SD memory card?

    If so, then you could copy the card to a USB "thumb drive" instead of using the card itself. Not sure if this would be faster though.

    The maps are not in the correct format to be installed directly on your computer, they must be on removable media. It is possible to create a virtual disk on your hard drive however, then copy the maps to it. There are a variety of programs to do this on Windows. I have used imdisk in the past, which is free.
  • Yes Boyd sorry about the scan disk reference, we call all the SD Memory cards that here at work since most all devices use the SD and Scan disk is the most prevalent we see here. I will give the virtual ware Project to my Bro as he works on that stuff on a regular basis.
  • Boyd 1960 Points
    Cool, glad I could help. BTW, I think you mean "SanDisk" without the "c". :)

  • Hi, I just registered here and I also just bought my first ever GPS unit. I really didn't expect it to be so complicated but I've been researching and banging my head against the wall trying to figure out what I need to buy/do to get this thing set up and working the way I would like it to.

    I just bought a Garmin eTrex 20 but still cannot understand which map format I should buy. At first I thought the DVD was the way to go but now I'm not so sure, although according to Garmin web site it is the only version that can be updated... not sure why. They also explain that the SD card and download versions will not interface with my computer which, to me sounds like a bad thing, but maybe I just need to learn more.

    I basically want to do two things:

    1)Use it for hiking and locating points in the woods (locally)
    2) Take it with me in the car for directions when I travel.

    Do I need to buy both a Topo map AND a street map?
    Would I need to swap SD cards to change from one map to another?
    Does the "Birds Eye" thing replace Topo map or work in conjunction with it?
    Is there enough space on an SD card for more than one map?
    Does it make sense to get a blank SD card and load all of my maps on that?

    As far as being in the woods, I don't plan on doing any traveling outside of my own locality but I would like to get the best map experience possible.

    This sticky gives a far better explanation than the Garmin web site. But I am totally clueless about using a GPS in general.

    Thank you in advance for any guidance!
  • Boyd 1960 Points
    If you are buying City Navigator (Garmin's street map product) then that is correct about updates. You can purchase either onetime or lifetime updates for the DVD version, but these cost extra. If you buy on memory card or via download there are no updates, you would have to buy another card or download.

    But for Garmin's topo map products, there are no updates regardless of format. You have to buy a new copy if you want it. They are not updated very often however and I'll wager that many people are still using US Topo which came out over 10 years ago.

    Totally up to you whether you need both topo and street maps. Garmin's 24k topo can give you driving directions. Their 100k topo cannot. Very few 3rd party topo maps can give driving directions. But you may not need this.

    You don't need an SD card unless your map doesn't fit in internal memory. Some people like to use them in case of problems through. A corrupt file could prevent the unit from working. If it's on a card, simply remove the card. In internal memory this is a bit more complicated sometimes.

    You should never need to swap cards UNLESS you purchase maps that are preloaded on cards by Garmin. They cannot be moved to another card.

    There are two flavors or Birdseye. Satellite imagery and USGS 24k topo maps. They must be purchased separately. The maps are scans of traditional paper USGS 24k topo maps which usually show a lot more "stuff" than Garmin's maps. But a scanned map (raster image) behaves much differently from an electronic map (vector image).

    The only thing that requires a lot of storage is Birdseye. I find it slows the device down to keep too much of it on a single card so I just transfer what I want at the moment. If you don't use Birdseye, a 4GB card may be all you will ever need. 8GB would be the next step up. You can store whatever mix of Birdseye, Garmin Custom maps and regular Garmin maps on both the card and internal memory.

    I have read that the eTrex 20/30 are sluggish when using Birdseye, so caveat emptor.
  • alanb 529 Points
    You might want to try some of the free maps available. For topo and custom maps look at GPS File Depot ( For routable street maps look at Open Street Maps (

    If you want to discuss this further you should probably start a new topic as we are drifting away from the theme of this topic.
  • OK... Sorry. Thanks for the info
  • I have just gotten a Montana and the CN on a SD card as a backup for my Nuvi. Running a route in Nuvi mode I do get Lane Assist displayed but not Junction View. Does anyone know if putting the JVC file (from my Nuvi) anywhere on the Montana will get it to display?
    BTW, both CN's are the same version.
  • sussamb 786 Points
    No it won't, the Montana doesn't do junction views.
  • Boyd 1960 Points
    I also have a Montana. It definitely does not support Junction View. Also, the term "Nuvi Mode" is a bit of a misnomer. The Montana doesn't have a Nuvi Mode, it has a Nuvi Dashboard. This just makes the map screen look like a Nuvi. It does not affect the function of the device in any other way, the Montana is always a Montana with completely different menus and functions from the Nuvi.
  • I now have a Garmin 600. Came with a GB Discoverer 1:50 map on SD card. Problem is cannot get
    device to recognise it. Several maps show under the Montana maps app but not
    Garmin support though recognising device, says 'no map'. There are several map descriptions showing on the device maps app all disabled but none matching GB map description.
    Maybe I have a blank SD Card.
  • Boyd 1960 Points
    I think you need to contact Garmin support. The map should appear on the list without the need to do anything special.
  • Thanks Boyd.

    There are several on the list with enable/disable options but they do not appear when enabled-maybe they are there awaiting map to purchased and downloaded.
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