Survey Controller is using the coordinate system information to calculate the distance from ground to grid. Please find below a useful picture out of Survey Controller Help content.

Elevation value get computed by using WGS-84 ellipsoid or in case you are using another Geoid model, to correct the elevation value as well.

Ground distance

A ground distance is the horizontal distance calculated between the two points at the mean elevation parallel to the chosen ellipsoid. If an ellipsoid has been defined in the job and the Distances field is set to Ground, the distance is calculated parallel to that. If no ellipsoid has been defined, the WGS84 ellipsoid is used.

Grid distance If the Distances field is set to Grid, the grid distance between two points is displayed. This is the simple trigonometrical distance between the two sets of two-dimensional coordinates. If the coordinate system for the job is defined as Scale factor only, and the Distances field is set to Grid, the Trimble Survey Controller software displays ground distances multiplied by the scale factor. Note - A grid distance between two measured GNSS points cannot be displayed unless you have specified a datum transformation and a projection, or performed a site calibration.

Ellipsoid distance If the Distances field is set to Ellipsoid then a correction is applied and all distances are calculated as if on the local ellipsoid, which usually approximates to sea level. If no ellipsoid has been specified, the WGS84 ellipsoid is used. Note - If the coordinate system for a job is defined as Scale factor only, ellipsoid distances cannot be displayed.

Hi Paul,

Survey Controller is using the coordinate system information to calculate the distance from ground to grid. Please find below a useful picture out of Survey Controller Help content.

Elevation value get computed by using WGS-84 ellipsoid or in case you are using another Geoid model, to correct the elevation value as well.

Ground distanceA ground distance is the horizontal distance calculated between the two points at the mean elevation parallel

to the chosen ellipsoid. If an ellipsoid has been defined in the job and the Distances field is set to Ground, the distance is calculated parallel to that. If no ellipsoid has been defined, the WGS84 ellipsoid is used.

Grid distanceIf the Distances field is set to Grid, the grid distance between two points is displayed. This is the simple trigonometrical distance between the two sets of two-dimensional coordinates. If the coordinate system for the job is defined as Scale factor only, and the Distances field is set to Grid, the Trimble Survey Controller software displays ground distances multiplied by the scale factor.

Note - A grid distance between two measured GNSS points cannot be displayed unless you have specified a datum transformation and a projection, or performed a site calibration.Ellipsoid distanceIf the Distances field is set to Ellipsoid then a correction is applied and all distances are calculated as if on the local ellipsoid, which usually approximates to sea level. If no ellipsoid has been specified, the WGS84 ellipsoid is used.

Note - If the coordinate system for a job is defined as Scale factor only, ellipsoid distances cannot be displayed.survey controller grid to ground gridtoground ground to grid ground distances ground