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Backup and restore pre-installed maps?

I bought a european Forerunner 945 which comes with the european topo-active maps pre-installed as well as coverage maps of the rest of the world.

How would I go to remove the maps from my device and install them later again? I now also have openstreetmaps of just the netherlands on it, works fine, so at the moment I have no use for the complete topoactive maps. ( gmapprom.img (North East) and D6185060B.img (South West) taking up about 6.5GB of data).

Could I just move the following files to my computer and restore them to my watch if I ever plan on using them?

D6185060B.img + gma

gmapprom.img + gma

And what are these files?

gmapbmap.img

gmapdem.img+ gma

gmapsup1.img + gma

gmapsup2.img+ gma

gmapsup3.img+ gma

gmaptz.img

Am I correct that the gma file is a decryption/unlock file for the img file?

(I have a openstreetmap file which consists of just the .img)

0 timgrose over 6 years ago

Not entirely sure but if could you not just reinstall them through Garmin Express. Also do you actually need to free up the space?

0 Fredderic over 6 years ago

Yeah you always have the option of reinstalling through Garmin Express, though the download time might be quite long. My suggestion is just to copy the files to your computer if you have the space there ;). What the different files are you can mostly figure out using google and looking at the file size.

Gma: The GMA (Garmin Map Activation) can be viewed as a signature file co-existing with the current unlock codes from UNL. Its main purpose is to validate the current unlock codes are indeed generated by Garmin.

DEM: A digital elevation model (DEM) is a 3D CG representation of a terrain's surface – commonly of a planet (e.g. Earth), moon, or asteroid – created from a terrain's elevation data.

Up1, up2, up3: Maybe upgrades? Got somebody claiming these are for golf courses though.

gmapprom: This seems to be the map image, I deleted this on my watch and it still works fine (using openfietsmap.nl map instead)

gmaprda: These are the "Road drawing accelerator" files, not sure how they work - on my watch I left them on, but other users report things still working after removing...

D6185060B (on 945) or D6185050A (on Marq): Not at all sure what this is, it might be the POI database, or the popularity map used to calculate routes.

Let us know what you find out by deleting the d618... or maprda files, if you figure out what they are for :)

0 FlipStone over 6 years ago in reply to Fredderic

Thanks!

The D6185060B.img should be the South-west europe main map, gmappromo.img the North-East europe map (found that in a different forum). The others were more unclear to me but thahks for the info!

For now it was also more a 'just wondering' question, don't think I actually need to free up space for now or have the desire to try it out. Indeed, I remember the first time connecting the 945 and having to download map updates through garmin express took a while.

Ah well, perhaps in the future or when I have the desire to load huge other maps or put tons of music on the watch ;)