The File->Configure->Coordinate System dialog

Here you can choose how coordinates will be displayed in the Xastir map window. You can choose:

• Decimal degrees (DD.DDDDD)
• Degrees and decimal minutes (DD MM.MMM)
• Degrees, minutes, and decimal seconds (DD MM SS.S)
• Universal Transverse Mercator
• Universal Transverse Mercator with "special zones" (Certain northern latitudes have zone sizes larger than everywhere else)
• US National Grid or Military Grid Reference System

Your selection here only changes the formatting of positions displayed in the lower status bar and on the map border if it is enabled.