Downloaded OSM Map won't allow transfer from Basecamp to GPS

Started by Finnkai, January 09, 2020, 01:00:34 PM

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I have downloaded an OSM Topo map of South America and successfully installed it so it is showing in Basecamp.  However, when I try to transfer segments onto my (aging) Etrex Vista C GPS using "Install maps", Basecamp says the device is not compatible with the map.  This has never occurred before with other OSM Topo maps I have downloaded.

I have inspected the files for the South America map and noticed that they do not seem to contain any .img files (which I understand are what I need for my GPS).  I observe that other OSM downloads I have installed have created a folder full of .img files.

Have I done something wrong?  Or is there a way to generate the missing .img files I need?



What you have said suggests that the map you downloaded is raster imagery, and not a map in Garmin's vector (.img) format. This type of map is not compatible with you old gps, which is what the error message is telling you.

I don't really use OSM, but know that some of their maps are distributed as tiled raster imagery. These can be used on newer Garmin handhelds if you convert them to .kmz files, however compatibility is still very limited. There are strict limits on how that imagery must be made, and you can only install a very small map.

This gets even more confusing however, because Basecamp does not have these strict limitations on raster imagery. That would explain why you can see the map in Basecamp. BTW, I would not use Basecamp with such an old device. I would use Mapsource, which is what your GPS was designed for. And (if my assumptions are correct), the map you downloaded will not work in Mapsource either.


Many thanks.  I did indeed try Mapsource and as you suspected, it still didn't work. 
However, Basecamp seems to work fine with other downloaded maps despite the age of my device.

From what you say, there is nothing more I can do with this particular map - a shame as it is really the best for hiking that I've found.

Thanks again for your help.


Well.... you have a GPS that's almost 20 years old! :) My first Garmin GPS was a Legend C, which is a "cousin" of your device. Think I got it around 2003 or 2004 (had a Magellan before that). These old eTrex units were fine in their day, but that was a long time ago.

Anyway, Garmin did not support raster imagery back then. That feature didn't come along until the first Oregon models (and IIRC, they made it backwards-compatible with the Colorado). But, even the newest models can only use kmz files with jpeg images no larger than 1024x1024 pixels and most devices only allow a total of 100 of those images. So, if you have a map with a 1-meter per pixel resolution, you'd only be able to load a map that is 10km x 10km.

But Basecamp doesn't have these limitations, so there are quite a lot of kmz files that work fine in Basecamp but not in any Garmin GPS (even the newest ones). If you want to use raster imagery, a much better platform will be a smartphone with an app. There are dozens of apps that support raster maps of (almost) unlimited size. And the apps range from free to only a few dollars each.