NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum

Yesterday I downloaded a gmapsupp.img from the All-in-One map page for my Garmin Dakota 20. The file is 6.6Gb, uncompressed, and I stored it on my computer's C: drive. My Dakota has a 16GB SD card, empty except for a <garmin> folder. When I tried to copy the downloaded file into the SD card I got a message saying it was "too large for this file structure" and said that gmapsupp.img was a DISK IMAGE FILE, which is not true, is it? Should I try changing the img extension for the move? Is there a 'file association' that I should change? There really shouldn't be a problem loading a 6.6GB file into a 16GB chip, should there? Any advice?

This question is marked "community wiki".

asked 26 Feb '13, 17:20

bwilsonduncan's gravatar image

accept rate: 0%

edited 27 Jan '16, 20:45

aseerel4c26's gravatar image

aseerel4c26 ♦

I guess your SD card is formated with a FAT32 filesystem, in which case you will not be able to put a file larger than 4GB on it. Possible workarounds:

  • Format your SD card with Ext2/3/4 or Ntfs. The problem with that is that your Garmin device is likely to only support FAT32 filesystems.
  • Use multiple smaller gmappsupp.img files, each showing a smaller area of the world. One advantage of this is that you can deactivate some of the map files, so that your device will feel faster. Another advantage is that you do not have to redownload the full 6GB if you just want an update of your area.
  • Generate a smaller map file, by removing some features. This is more technical, but can be an interesting solution.

Concerning the "gmappsupp.img is a disk image file" question, this is just Windows's silly habit of guessing a file's type from its name. Ignore it.

permanent link

answered 26 Feb '13, 17:50

Vincent%20de%20Phily's gravatar image

Vincent de P... ♦
accept rate: 19%

edited 26 Feb '13, 17:51

As Vincent says, I would be very surprised if your GPS supports a filesystem that supports individual files larger than 4Gb. I'd leave your filesystem formatted as FAT32 and find a download that's smaller than 4Gb instead.

I presume that the download that you're trying to use is from here. According to the wiki page, you can contact the creator of these files via OSM. In fact a number of people have already asked him exactly this question, but with no reply yet. I suspect that what has happened is that an automatic process is used, and the file size (before all those delightful French buildings were imported!) was < 4Gb, but now it isn't.

If you don't want the whole of Europe, then you can try one of the other Garmin maps, such as from here, and choose which areas you want.

Another option (which is a bit more work, but would work if you did want the whole of Europe) which be to download the OSM data for Europe, filter out what you don't want, and then use mkgmap to create a map in a style of your choice.

permanent link

answered 26 Feb '13, 19:21

SomeoneElse's gravatar image

SomeoneElse ♦
accept rate: 16%


This might be an easier solution; Format the SD card in exFAT. This is a SD card Format type that supports files bigger as 4Gb. Garmin seems to support it: "Cards larger than 32 GB are typically formatted in exFAT1"

According to microsoft exFAT can be used also for smaller cards than 32gb:

Here is a table to see which windows systems support exFAT, basically all starting by windows 7.

building exFAT card manuals: windows procedure:

Ubuntu and debian procedure:

Hope this helps!

permanent link

answered 18 Sep '17, 16:24

leeuwtje's gravatar image

accept rate: 0%

edited 18 Sep '17, 16:43


exFAT is a solution, yes, but only if the Garmin device has a filesytem driver in its firmware updated to support it. It's not clear (without performing tests) which file systems it will support and will accept to mount. NTFS support is unlikely, ext2fs could work but not sure that Garmin will automount it if it expects to mount only FAT-like systems. So the best you can do is to try formatting the SD card and store a small file on tit to see if it can see it (e.g. a small JPEG photo if it has a feature to render photos, or any other small map image file). You may need a firmware update on your device to accept new SD cards.

(18 Sep '17, 23:17) Verdy_p

Anyway, you should not use any file made for all Europe, but download files for specific countries (or regions of large countries): you can place multiple files on your SD card even if it's formatted with FAT32 and so has large cluster sizes (you won't waste a lot of space given that individual files are much larger than cluster sizes), and it will be easier to update maps for selected regions.

(18 Sep '17, 23:20) Verdy_p

Follow this question

By Email:

Once you sign in you will be able to subscribe for any updates here



Answers and Comments

Markdown Basics

  • *italic* or _italic_
  • **bold** or __bold__
  • link:[text]( "title")
  • image?![alt text](/path/img.jpg "title")
  • numbered list: 1. Foo 2. Bar
  • to add a line break simply add two spaces to where you would like the new line to be.
  • basic HTML tags are also supported

Question tags:


question asked: 26 Feb '13, 17:20

question was seen: 11,931 times

last updated: 18 Sep '17, 23:20

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum