Spectra Precision FAST Survey Reference Manual - Manual (Page 168)

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In the Intersect mode, the first screen always displays the target point on the line (or the extension of the line),
perpendicular to the setup or station point. When the first reading is taken, the program will display the In-Out distance
to the line along the line-of-sight. Regardless of the Reference Centerline settings, the instructions will be In-Out to the
target line. However, if Reference Centerline is active, the station and offset to the reference centerline will be shown,
with an "*" prefix.
When staking a line defined by points with zero elevation, the cut or fill values will be displayed but should be ignored.
Notice that the screen expands to show more graphics by pressing the down arrow key.
Total Stations/GPS, Perpendicular to Line:
When configured for the Perpendicular to Line method, the program will
show the direction and distance to move to find the nearest point on the line to the measured point. The instruction