Garmin GPSMAP 495 - Manual (Page 129)

GPSMAP 495 Owner’s Manual 121
Setting up and Using Sonar > Using the Sonar Page
Using the Sonar Page
When combined with a GSD 20 or GSD 21 Sounder Module, your
GPSMAP 495 becomes a powerful fishfinder/flasher with the Sonar
Page. If a GSD 20 or GSD 21 is attached, but the unit does not
detect a transducer, a “Sonar Turned Off” message appears across
the Sonar Page. If a GSD 20 or GSD 21 is not attached, the Sonar
Page only appears when the unit is in Simulator Mode.
The middle of the page contains a right-to-left moving sonar image
of the water beneath your boat. Items appear as they pass under your
transducer. Those items on the right side of the screen are closer to
you than those on the left. Along the right side of the screen is an
adjustable scale that reflects the depth of the area being shown. The
top-left corner shows the Adjustment Option, the depth, and the
water temperature.
Sonar Page
The sonar returns show as red (strongest), then orange (strong),
yellow (medium), green (weaker), and blue (weakest). The Fish
Symbols option allows you to view the actual sonar data, a fish
symbol or a combination of both. When the unit is set to Dual, the
appearance of the fish symbols changes. Fish symbols from the
center of the beam (200 kHz) are solid (or narrow arches), but the
returns from the edges of the beam (50 kHz) are hollow (or wide
arches).
The Sonar Page can also be set to show a split screen view of a
zoomed portion of the sonar, bottom lock (screen scaled from the
bottom up), or a combination of these options. For example, you
can choose to show dual frequency at a 2X zoom (Dual 2X) on one
half and normal range dual frequency (Dual) on the other half. The
current display mode is shown at the bottom of each sonar screen.