Thursday, August 6, 2009

Adding multiple maps in Garmin Nuvi 255w GPS

Theoretically, the Garmin Nuvi GPS navigator can be loaded with hundreds of map. The limit is on the maximum file size (about 2GB per file) and available storage memory.

The maps are stored in specific mapset files with *.img extension in the flash memory of the GPS unit. Each mapset file contains one or many maps in it. Beside that, the Garmin GPS navigator can also recognise and load up one additional mapset file from SD card residing in the "Garmin" folder and named as "gmapsupp.img".

Here are the mapset files supported by Garmin Nuvi 255w GPS navigator:
  • gmapbmap.img - the default base map
  • gmapprom.img - the primary mapset
  • gmapprom1.img - the secondary mapset
  • gmapoem.img - the OEM mapset that cannot be unselect by user (if it exist)
  • gmapsupp.img - the supplemental mapset which you can have one in the GPS flash memory and another one in the attached SD card.
Therefore, the Garmin Nuvi 255w GPS supports up to 6 mapset files, including 1 in SD card. Normally new maps installed by the user will be stored in gmapsupp.img.

You will lost all the maps in the previous mapset file if it is overwritten by a new file with same filename. If you want to keep the existing maps, ensure that you store the mapset file with an unused filename (from the 5 filenames above). Alternatively, you can make use of special tools to merge new maps into existing mapset file.

You can view the name of your base map in Tools > Settings > System > About > Basemap.

You can view the name of maps in the other mapset files in Tools > Settings > Map > Map Info. There, you can tell the GPS to load the map by checking on its name, or not to use the map by unchecking it.

In case there are 2 or more non-overlaping maps available for the same location, the map with the highest priority number (defined in the map itself) will be used by the GPS.

Note that certain map which are locked by vendor need a 25 bytes unlock key stored in a *.unl file in the same folder and with the same name as the mapset file where the locked map is stored in.

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16 comments:

  1. UnknownAugust 10, 2010 at 5:26 AM

    Where do i find "Tools > Settings > System > About > Basemap.
    You can view the name of maps in the other mapset files in Tools > Settings > Map > Map Info."
    Having attached garmin to pc using USB cable i am not sure what to go in to.

    ReplyDelete
  2. Voyager8August 10, 2010 at 11:44 AM

    Hi William,

    They are the options in our Garmin GPS.

    You need to unplug the USB cable and use the GPS as normal.

    ReplyDelete
  3. Nitin UleOctober 15, 2010 at 2:47 PM

    thanks a ton fro your information it was very useful thanks fro sharing.. now two maps on my Nuvi 255W.
    :-)

    ReplyDelete
  4. AnonymousNovember 7, 2010 at 11:36 AM

    Thank you for the great info

    ReplyDelete
  5. dirty-noobDecember 21, 2010 at 2:42 AM

    tried adding new map on sd card and northing works with all the names i tried lol

    ReplyDelete
  6. Voyager8December 21, 2010 at 8:38 AM

    @dirty-noob

    You need to create a "Garmin" folder and put the maps inside it.

    ReplyDelete
  7. Adriane DutraApril 12, 2011 at 8:54 PM

    Why won't my garmin 255w read the SD with gmapsupp.img Brazil map I have there? Can you help me? Thanks

    ReplyDelete
  8. Adriane DutraApril 12, 2011 at 8:55 PM

    Why won't my garmin 255w read the SD with gmapsupp.img Brazil map I have there? Can you help me? Thanks

    ReplyDelete
  9. Voyager8April 12, 2011 at 9:24 PM

    @Adriane Dutra

    You need to create a "Garmin" folder and put the maps inside it.

    ReplyDelete
  10. Adriane DutraApril 13, 2011 at 5:50 AM

    It worked! Thankssssss!!

    ReplyDelete
  11. UnknownMay 11, 2011 at 3:23 PM

    Thanks for your advice. I was able to add one map on my SD Card with the name gmapsupp.img. I tried to add another map to the device with the name gmapsup2.img but it did not work. How can I add additional maps?

    ReplyDelete
  12. Voyager8May 11, 2011 at 3:28 PM

    @ryanbm3

    You can put a few maps inside gmapsupp.img by using gmaptool.

    Refer to here:
    http://voyager8.blogspot.com/2009/08/using-gmaptool-to-combine-multiple-maps.html

    ReplyDelete
  13. Nitin UleAugust 20, 2011 at 1:21 AM

    join the maps with Gmaptool and you can keep one map gmapsupp.img of 20 countries Maps in one file. But very useful and detail information. thanks

    ReplyDelete
  14. munge83October 26, 2011 at 6:23 PM

    I diden't try your method because I always use MapSource program to generate a custom maps. All people don't need the whole maps in garmin devices. I't slows down a processing of device and maps sometimes interfere with each other. I think it's better to create your own custom map with MapSource an then transfer it as on .img file alwready unlocked in MapSource with JetMous generator. This generator still works even for the new maps like City Navigator Europe 2011.20. I haw totorial how it's done with MapSource. Try to look for my web page. http://iw3b.info

    ReplyDelete
  15. frankyg1March 1, 2012 at 4:10 PM

    I DOWNLOADED A GARMIN FILE MAP ONTO MY HTC SENSATION,CAN I TRANSFER IT TO MY Garmin nuvi255w,do I need an sd card

    ReplyDelete
  16. Voyager8March 1, 2012 at 4:42 PM

    @frankyg1

    Not necessary.

    You can copy the file into the SD card, and slot in the SD card to your GPS.

    Alternatively, you can use a USB cable to connect the GPS to your computer, then you will be able to see its internal storage, and copy the file into it.

    ReplyDelete