In Surfer, you can import the DLG in UTM and then convert the map to display lat/long. To do this:
- Click Home | New Map| Base | Base, select the DLG and click OK. The DLG file is imported in UTM coordinates. The coordinate system for the base layer should already be filled in.
- Select Map in the Contents window.
- In the Properties window click the Coordinate System tab.
- Click the Change button.
- Select Predefined | Geographic (lat/lon) and select your datum (usually World Geodetic System 1984).
- Click OK and the map is converted to Lat/Long units.
Using Surfer 7 or 8, in the SDTS-TVP Import Options dialog, check the check box in the lower left for Unproject Coordinates, then click OK.
Updated October 24, 2017