To configure the project's Coordinate Reference System (CRS), open the Project configuration menu.

In this menu, you can set the CRS and choose the measurement system in the Project coordinate/measurement system section:

g-Space offers a vast selection of predefined CRS.

The easiest way to find the one that suits your project is by entering its EPSG code into the search field:

If the CRS of the imported data differs from the project's CRS, you can specify a different EPSG code for the import:

In this section, you can also choose the measurement system from three options: Imperial, Metric, or Field (coordinates in Metric and depth in Imperial):