Same map, different typ files?

[LostAgain]

Hello All,

I'm wanting to use copies of the same map on the same device with each containing a different .typ file, so I can switch quickly between one or another to have the map elements displayed with different colours etc..

Just putting 2 separate maps with different .typ files on the device (276CX) doesn't work as it only recognises and shows one of them.

I imagine something that identifies each map has to be changed so the device thinks it's looking at two different maps.
What is it that has to be changed?

Thanks

 

[Nuvi-Nebie]

You need to have only one map enabled at a time, you can control which map is enabled with :-

 

[LostAgain]

Doesn't work that way unfortunately, I've already tried that.
The problem is the other copies I put on the 276 do not show in Configure Maps.
Only one will show, regardless of how many copies I put on there.
Tried with one on the device and one on an SD card, same happens, only one shown.

There must be something else Garmin devices use to ID the individual maps, and I believe that has to be changed for each map so they appear as different to the 276.
I just don't know what that is that has to be changed.

 

[Nuvi-Nebie]

I think this may depend on how you are sending the maps to the 276, on older Garmin units the maps are all contained in a single file called gmapsupp or gmapprom, so if you generate a map, re-name it to gmapsupp and send it to the 276, this file will be replaced when you generate a second map which is also re-named to gmapsupp, on newer units you can have different names for map files eg. Map1.img and Map2.img

It is possible to have a single gmapsupp file that contains two or more seperate maps but all the maps have to be combinded into a single gmapsupp file using a Map Install program, this can be achieved using Garmin Basecamp, where both map files are visible to Basecamp as say Map1 and Map2 and then using the 'Install Maps' option to select both maps, Basecamp will then create a single gmapsupp file containing both maps and send it to the 276

 

[LostAgain]

Copy paste from an MX-Linux system via USB is how I get anything on or off the 276.
I've never used Basecamp or anything else to send maps to any of my Garmin devices, only copy > paste, might have a look at that shortly.
Firmware on the 276 is the latest, happened with older firmware too.
Viewing them in a file explorer after they've been pasted to the 276 they all show as expected and the amount of storage used on the device matches.
Testing each one individually with only the one on the 276 they all work fine.
But put any more than one on there and only one will show in Configure Maps.

 

[Nuvi-Nebie]

I'm still not sure if the 276 uses the single map file 'gmapsupp.img' system or whether it can accept multiple map files with different names like Map1.img and Map2.img, when you copy and paste files to the 276 what file names are used ?, eg. are they named gmapsupp.img ?

The point of using Garmin Basecamp is that it :-

1. Combines mutiple maps into a single file if needed
2. Gives any single file created the correct name
3. Sends any single files or mulitple map files to the correct memory area (internal / SD)
4. Sends any single files or mulitple map files to the correct folder name / location

If you get any if the above wrong your 276 won't 'see' the maps

 

[LostAgain]

As I mentioned previously, when I put only one of the maps at a time on the 276, it works fine, this is the same for both copies I am trying to use, provided there's only one at a time on there, regardless of which one, they work as expected.
So it's 'seeing' the maps ok, just not showing them all when there's more than one copy on there.
It appears random which one is shown, it will show either one or the other, but never both.
This behaviour is the same with the 276, a Montana 610 and a Montana 700.

With the 276 (610 and 700 also) the maps can be named anything, so long as they have the .img extension.
When I copy and paste to the 276 they are named shonky-19-10-20.img and shonky-dark-day-24-10-21.img, I've tried other naming formats, none of which were successful.
They are pasted to the Root folder, which is where the original topo map that came with it when I bought it was found.
On an SD card there needs to be a folder named Garmin created and any maps placed inside that.
The maps I used to make a copy of are the free topo maps of Australia, provided here - https://shonkylogic.net/shonkymaps/

From what little time I've had to research it, I believe I need to use GMapTool to change either the PID, FID or Map ID or a combination of those in each map, so that the device thinks the maps are different, or as you suggested try using Basecamp to combine them into a single map, or perhaps change the ID's with Basecamp, if that's possible, and see what eventuates.

 

[Nuvi-Nebie]

If your 276 can 'see' img files with different names then Basecamp wouldn't create a single file with a special name, I would expect it to place files either on internal memory or SD in a sub folder called /Garmin or /Maps and as far as I know Basecamp won't change map ID names

I would definitely try shorter file names for your maps, old versions of Windows for example only allowed 8 characters for a file name so ABCDEFGHXXX.img and ABCDEFGHYYY.img would be seen as the same file, I would also not use '-' just in case it is an invalid character, try say first.img and second.img, or something short with no spaces or other invalid characters, just a to z and 0 to 9

 

[LostAgain]

Just renamed them to 'one.img' and 'two.img' to eliminate any possibility.
Didn't work, same happens.
I don't think it's anything to do with how the files themselves are named, if it was and there was illegal characters used they wouldn't work individually either, but they do.
I think it's something to do with the internal header data of the .img file that Garmin devices use to determine if it's a different file or not, I just have to try and figure out what that is, I thought perhaps someone here had done similar before and might have known what needs changing.

The screenshots show what I see when viewing the contents of the Garmin folder via a file manager, versus what's shown in the Configure Maps settings.

It's calling the ShonkyMaps as ShonkyMaps, not 'one' or 'two' as I've named them, and it also calls the other maps different to the filenames I've given them, which leads me to believe it's getting the names it uses from something internal inside the .img files.
Because I'm putting 2 maps with what the device sees as the same name, my guess is it's only showing one of them by design.

I was incorrect above also in post number 7, they aren't pasted to the device's Root directory, but in the Garmin folder.

EDIT: I should also mention that I have tried a factory reset of the 276, that didn't help either.

 

[LostAgain]

Managed to get it to show both at the same time, they can be enabled or disabled ok.
Had to change the Mapset Name and Map ID of each tile in of one of the copies.
Only issue now is the copy I changed refuses to use it's own .typ file for some reason, which was basically the reason for this experiment, lol.
I have no idea where it's getting it's colours from but they are completely different to the colours in the .typ file that's in the .img file