Thread: Convert garmin .img pseudo-NT to non-NT? I know it's possible, but how?(SOLVED!!!)

TUTORIAL for an "almost" automated solution:
Use the third version of the program [Only registered and activated users can see links. ] created by r0cker (download link also at post [Only registered and activated users can see links. ] and r0cker's [Only registered and activated users can see links. ])

1-Extract .gmp file from .img(pseudo-NT, single map) using GMapTool
2-Use GarminGMPExtract003.exe with the .gmp file and obtain the subfiles (.LBL, .NET, .NOD, .RGN and .TRE) from it
3-then join these five subfiles (.LBL, .NET, .NOD, .RGN and .TRE) with GMapTool as a non-NT img (short header in options) and get the converted non-NT .img file

Now, for example, you can open it with any version of GPSMapEdit, edit and save it as a *.mp format or any other thing that you want to do.
In fact, the non-NT .img file you obtain, CAN BE OPENED with OLD GARMIN UNITS (NT unaware) and with any map editing/decompiler program that opens non-NT mg's files.
Another useful program is GPSmap0085 (specifically this version 0085) that let you extract house numbers from the .img.

Note: The only version available on the web of [Only registered and activated users can see links. ] program is the FREE version (NOT the ROUTABLE), so you can get the map with house numbers, but you cannot get the routing info.
Eventually, combining what you get from GPSMapEdit (here you get all map info, including routing, but NOT house numbers) and GPSmap0085 FREE (House numbers, but NOT routing) you could get a full map, but this need programming.

Note 2: if anyone have GPSmap0085 ROUTABLE version, please share here
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How it was worked out...

See post [Only registered and activated users can see links. ]
and posts [Only registered and activated users can see links. ] and [Only registered and activated users can see links. ]

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--Original Post:

I'm trying to know how to convert pseudo-NT (by cgpsmapper) to non-NT garmin maps.
I know it is possible because GPSmapedit version 1.0.66.7 can interpret and decode pseudo-NT created by cgpsmapped (which is not the real NT from garmin that can't be decoded by any program at hand)
(this apparently was a bug in GPSmapedit, because neither earlier versions or newer version can decode pseudo-NT, only this 1.0.66.7 specific version)

This is what i have:
I use as source map one that came in cgpsmapper 0100d installation folder here:
gdansk_routing\MP_source\gdansksopot.mp
I named it example.mp

What i did was, compile the img with and without NT enabled using cgpsmapper 0100d and get:
example.img (non-NT compilation)
exampleNT.img (Pseudo-NT compilation)

so i can see the differences.

Then, using GMapTool 0.8.143, splited both img to their respective subfiles (you can extract each subfile from the img directly, but to be sure...)

So i get: .RGN; .TRE; .LBL from example.img
and
.GMP from exampleNT.img

Let me explain: the idea is to convert pseudo-NT to NT maps. So if i happen to have a pseudo-NT map and if i could extract the RGN,TRE,LBL(NOD etc..) from its .GMP I'm DONE!!
In this example i have both files pseudo-NT and non NT, so it should be easier comparing both.

This is how GMP file is structured:
GMP header
TRE header
RGN header
LBL header
TRE rest of TRE file
RGN rest of RGN file
LBL rest of LBL file
(this is located in the GMP file as i put here, one segment after another)

So i can create TRE,RGN,LBL files extracting the info from the GMP file. (i called them NT.TRE; NT.RGN; NT.LBL)
(for the moment i can do this by previously knowing each file zise, because i have the non-NT version also!!, ... but keep this for later)

If now, using GMapTool, i join these "from NT" subfiles i get an img garmin map. BUT these map fail to load in GPSmapedit.


Comparing the files (pseuso-NT/non-NT subfiles) THERE IS A DIFFERENCE in the headers.

SO the info inside the pseudo-NT and non-NT img is the same except for the headers of the subfiles.

Here you can see the differences

Spoiler: images

[Only registered and activated users can see links. ]

[Only registered and activated users can see links. ]

[Only registered and activated users can see links. ]

the rest is exactly the same, the same info, nothing changed.
You can see in the last image, after the LBL header is the rest of the TRE file which is exactly the same as in the TRE file extracted from the non-NT version.
The only thing that changes between pseudo-NT and non-NT is a few bytes in the headers of the subfiles (besides they are splited and re-ordered in the GMP file)

Apparently the headers were encoded or something, Anyone can realize what are these tiny change that were made to the header?

If we know that we can convert from pseudo-NT to non-NT

I tried with ROT-13 encoding/decoding but it's not it.
I really know nothing about this :P , so perhaps some hacker or something could help.


Thanks in advance