I am using Global Mapper 21 and i want to reproject raster/vector data with custom geographic parameters.

I can do it with ArcGIS (create custom geographic transformation). I have 7 parameters that can be used on method coordinate frame (at least in this name i can find this method in ArcGIS) but cant find any option to use this parameters in Global Mapper. I want to transform from epsg:3127(or 6870) to 32634 and vice versa also from 28404(or 2462) to 32634, i have 7 parameters already.

  • Use the "EPSG Code Finder" if you know the transformation numbers. You don't need to create a custom transformation in this case. – gktscrk May 19 '20 at 19:27

When loading the data, unless it has a known geodetic reference file, the program will prompt you to enter its CRS. You can use the Search by EPSG Code button upon loading as below:

enter image description here

For your first example, this should be "3127".

After this, you'll have set your layer's (and, for now, also your project's) CRS. To change this (in your example you want to change this into your target CRS, you go to: "Tools" > "Configure" > "Projection" -> "Projection". Again, in this menu you'll be able to set your specific CRS based on the EPSG code (32634) using the Search by EPSG Code button:

enter image description here

Everything will be re-projected when you accept this change.

As you know your EPSG codes, you don't need to manually add any transformations (but if it was something special, you can go through the Add Datum options -- as you don't need this, I am not going to detail this pathway as it is liable to introduce more errors than just returning the exact CRS through the EPSG code).

If your files load without prompting for the CRS projection, you can determine and change an individual layer's projection by double-clicking on it in the "Control Center" (or right-clicking and choosing Options) and going to the "Projection" tab. The global projection (also the one in which you view everything) will always be set from the "Tools" option as described above (but will start out the same as your first loaded layer's projection).

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