Easiest way to do that:
1. Open the Settings dialog > GPS tab and then tap on the button where you can see the current projection
2. The Select projection dialog box appears
3. Tap on the Customize button to edit the Datum and/or the Projection parameters on the Custom projection dialog box
4. Enter your parameters and finally tap on the OK button to save the modified parameters into the Windows Registry
Please, note that the modified parameters can't be available on a different device (because of Step 4.)An other, but a little bit harder way is to open and edit the projection parameters file directly in a simple text editor. The projections are located in the Grid.txt file in the \BIN directory of the DigiTerra Explorer's SD Card or it can be found on the install path of the software on a desktop (usually it is "c:\Program Files\DigiTerra Explorer v6")
