Garmin GPSMAP 178C Owner's Manual

Also see for GPSMAP 178C: Specifications Flush Mount Template Manual Owner's manual

Contents

Garmin GPSMAP 178C Owner's Manual Manual pdf 49 page image

39ReferenceSonar Tab Options,If the unit is unable to track the bottom for any reason, the digits in the depth windowfl ashes on and off to alert you that the unit is not tracking the bottom.Scale — controls the depth ‘Scale’ displayed vertically along the right side of the graph. The depth‘Scale’ can be configured to display four different ways: as an ‘Overlay’, in the ‘Corners’, with ‘Basic’or ‘No Scale’.Color Bar — shows a gradient scale of the current Target Level setting (see page 35).Flasher — with the ‘Flasher’ active, a graphic Flasher representation is displayed on the far rightside of the graph. This graphic Flasher displays structure and bottom returns much the same as atrue Flasher. You may find this feature particularly useful when using ‘Fish Symbols’.Temperature Graph — toggles On or Off the display of a temperature graph on the Sonar Page.The graph is synchronized with the returns on the sonar display.Background Color — sets the background color on the Sonar Page to Black, Blue or White.Keel Offset — used to offset the surface reading for the depth of a keel. This makes it possible tomeasure depth from the bottom of your keel instead of from the transducer’s location. Enter a posi-tive number to offset for a keel, or enter a negative number to compensate for a large vessel thatmay draw several feet of water. The ‘Keel Offset’ is reflected in the depth reading.Map Split Sonar Detail — controls Map/Sonar Page sonar split range scale. ‘Full Range’ showsright side scale of 2X or 4X split Sonar Page. ‘Maximum Detail’ displays what is shown on the leftside of a split sonar screen.Calibrate Water Speed — this is only available if you are using a speed-capable transducer/sensor.Calibration is required to ensure that the Water Speed displayed on your unit is accurate. The unitautomatically uses the GPS ground speed, if it is available, for comparison on the calibration. If aGPS ground speed is not available, use either your boat’s speedometer reading (not always accu-rate) or a stopwatch to determine your speed over a certain distance (distance / time = speed). It isrecommended that the calibration take place in water having little or no current.Main Menu—Sonar TabDepth Scale (Overlay)Color BarFlasher