This dialog lets you select the Coordinate Reference System (CRS) for the survey.
Choose from Local, UTM, NAD83 (Conus), NAD27, OCRS or WISCRS. Others will be listed as they are added.
Select the corresponding zone. The zone data for each zone is stored in the TpcZone.dat file in the TPC program folder and can be edited in any text editor. The ZONE.DAT file is self documenting.
Each zone in the TpcZone.dat file contains parameters based on a horizontal datum. When you select a reference system and zone, TPC resets this to the corresponding horizontal datum.
Choose this button to edit the ellipse parameters for your grid. If you are modifying the survey grid, these values are stored with the survey and used for all its grid geodetic computations. Any changes you make are also stored in TPC registry and will be used the next time you start a survey.
If your survey is in Feet, specify whether you want to convert to meters using the International Foot (0.3048 M/FT) or the US Survey Foot (0.3048006096 M/FT).
Update the CRS of the survey.
Return without updating the CRS.