Garmin Sounder GPSMAP 135 Owner's Manual page 17

Data Field
Thermocline
Whiteline
The sounder page lets you use the GPSMAP 135 as a fishfinder. The top of the
screen contains any of seven selectable data field options, while the middle of the
page contains a right-to-left moving sonar image of the water beneath your boat.
(Note: Items appear on the screen as they pass under your transducer. Those
objects appearing on the right side of the screen are closer to you than those on
the left.) Fish are displayed as a darkened arch or a fish icon in three different
sizes. Thermoclines (layers of water separating warmer water above from cooler
water below) are shown as shades of gray.
The area of strongest sonar return (or whiteline) is displayed as a mix of light
and dark checkering. Typically, the bottom will be the primary source of the
whiteline. A thin whiteline indicates a softer bottom while a thick whiteline shows
a harder bottom. A black line is used to show the point where water meets the
whiteline. This black line will follow the bottom contour, along with any signifi-
cant objects lying on the bottom. Along the right side of the screen is an
adjustable scale which reflects the depth of the area being displayed. The status
bar at the bottom of the page displays satellite signal status, digital depth, and any
triggered alarms. More on the sounder page may be found on pages 25-35.
Range Mode
Fish Arch
Status Bar
GETTING STARTED
Sounder Page
B
A
A. When adjusted correctly, the bottom is outlined
by the whiteline. To adjust the whiteline, see page
30.
B. Pause the screen by pressing the EDIT/ENTER
key at any time. To continue screen movement,
press EDIT/ENTER again.
Pausing is used to allow more time to examine the
screen display and is necessary when using the
underwater waypoint function.
7