Furuno GP-3500F - Manual (Page 209)

11. VIDEO SOUNDER OPERATION
11-37
SMOOTHING
Smoothes echoes to present stable display. The higher the setting the greater
the smoothing.
DEPTH INFORMATION
Selects the size of the depth indication, L (large), S (small) or OFF.
TEMPERATURE GRAPH
Turns the temperature graph on or off.
Note: This graph is not available on the HORIZONTAL 2:1 and VERTICAL 3:1
displays.
ZOOM MARKER
Turns the zoom marker on or off on the single frequency display for the
bottom-lock or bottom discrimination display.
PLAYBACK SNDR IMAGE
Reviews the past picture. For further details, see paragraph 11.14.
SPEED CALIBRATION, TEMP CALIBRATION,
DEPTH CALIBRATION, ASTC SPD CALIBRATION
See the installation manual.