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

Thanks, i like your method, in a way is similar to "add zeros" method, preserving absolute offsets of the data, but your method is even faster, i like it!!
Obviously, for proper conversion, it is needed to do the whole "subtract" offsets thing and you get a proper non-nt img with a proper size.
But with your method you get a quick way to obtain the the non-nt img and then the *.mp (polish format map). Even if the img is oversized, the .mp data is not, so is perfect for that.
And that is ultimately what we want it for. The oversized img is not needed anyway as the original "nt whatever" is already available if we don't want the data.

Originally Posted by kunix

2.1.2) replace the GMP header with XXX header in YYYYYYYY.XXX

To be clear, i would add that the XXX header need to be "overwritten" to whatever is at the beginning, and NOT inserted if you "insert" you move the data and loose the original absolute offset position, and it won't work.

Definitely, "add zeros method" is deprecated in favor of yours.

Originally Posted by kunix

Well, I wasn't talking only about headers, I was talking about some data referring other data through specifying the offset. You can't fix that without deep IMG format knowledge.
But your doc and the fact that you can convert CarteBlanche convince me that your way is just fine.

There was NO differences in the "body" of the sufiles, comparing pseudo-nt to non-nt (not even a byte). The only differences where in the headers, so no need to correct anything in the data itself.

Originally Posted by kunix

And also all maps converted this way (I've tested NT and pseudo-NT) worked fine on Garmin devices.

You say here NT (real NT?), what do you mean, you say you could open it on Garmin devices, but Could you open NT(real) converted maps in Gpsmapedit?

Could you point me to a link to a real NT map?(better if it is a small size download!)