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

Originally Posted by testlelelala

The header size is located in the first two bytes of each header.
Example: When you found "GARMIN RGN" before that you see two bytes 7D 00 it means x7D which after conversion to decimal is 125 bytes.
Analog with LBL (xEC-->236 bytes), NET(x64-->100 bytes) and NOD(x3F-->3 bytes)
The only one "odd" is the TRE header that is larger that what you see in the first two bytes, because it could change with copyright info, nevertheless this extra info is not necessary, you could only grab the size that you get from the first two bytes.

I'm afraid it's not true. I've seen a map with GMP subfiles having some data (not copyright) beyond the standard header size for almost all headers (except 2, don't remember which ones), but before the next header. This map was an NT one, actually.

Originally Posted by testlelelala

But i don't see where in his utilities he reverse engineered the pdeuso-NT format, or even more, where, he reverse engineered the NT format as he is claiming.
It would be nice he accomplished that, it would be nice Wu Yongheng explain us.

See, for example, gimglib.c line 153, it parses GMP headers below.
Also function create_patch at gimgunlock.c line 95 should be able to handle NT map data.

Originally Posted by kunix

I remember that. But don't you think it's true only because your map is too small and you don't test all the available data formats? It would be nice to compare this way something like CNE, huh ?

The example i uploaded here in the thread is just that, an example. I compared and analyzed bigger and complex maps (non-nt and pseudo-nt) and came to some conclusions, this conclusions came from this complex maps and not from the "example" map, the example map is the one i selected to upload here to share, i thought this was obvious.
Obviously this conclusions could be wrong, if you found one counter-example please provide it here so we can analyse it.

Originally Posted by kunix

I'm afraid it's not true. I've seen a map with GMP subfiles having some data (not copyright) beyond the standard header size for almost all headers (except 2, don't remember which ones), but before the next header. This map was an NT one, actually.

Definitely i'm talking about non-nt and pseudo-nt maps, which are the ones treated in this thread (NT maps are different!!!).
And YES the first two bytes in the header give you the size of the header. I'm not the only one saying this, see [Only registered and activated users can see links. ] and seacrh for "Header Length" string.
Also, there is not a "standard header size", you get the size from the first two bytes, it could change between different maps.

Regarding this i downloaded the Malsingmaps which are NT.(in this case this is the only one i analysed, no diversity here besides the several individual maps included)
What i found is that TRE, LBL and NET headers have a length as it is given in the first two bytes of each header, as in the non-NT/pseudo-nt maps.
On the contrary RGN and NOD headers don't. Further analysis make me to believe that the extra data for example in the RGN header, is in fact not part of the RGN header and is another header of x4a length (74 bytes) (info given in the first two bytes of this extra data). This extra header point to some "dictionary" data.
If you download Malsingmaps you will see what i mean.
It is difficult to explain here in a short comment, and it is useless to do so as i don't have any other relevant info.
The extra data in the NOD header doesn't seem to be another header.
From what i saw to convert from NT maps to non-NT maps it would take definitely more work and i think ¡'m not capable of doing this.

Originally Posted by kunix

See, for example, gimglib.c line 153, it parses GMP headers below.
Also function create_patch at gimgunlock.c line 95 should be able to handle NT map data.

If you explain how can i use it to convert from NT to non-nt, or at least pseudo-nt to non-nt it would be great, i just don't see how you can accomplish this with this utilities.

Spoiler: large pic

[Only registered and activated users can see links. ]

My Mapedit 2.077.1 as only a v1 license. Can this be the problem?
TIA

Cnfhbr, Ed_slv
That message number 0x1F78 ("The sub-map %s is in NT format which is not supported by GPSMapEdit.") can be shown from two different places.
One more patch

Code:

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