Garmin GPSMAP 580 Owner's Manual page 78

Setting Up and Using Sonar
Sonar Adjustment Options
Scroll—allows you to adjust the rate that the sonar display scrolls
from right to left. If you are sitting still, or the sonar display is
moving too fast, slow the scroll rate or pause the scrolling.
Range—allows you to set the display depth range used for viewing.
The unit can be set to automatically track the bottom or set to a user-
specified depth range.
Zoom—allows you to select a display zoom scale or split the
display. When a scale other than No Zoom is selected, the
Adjustment menu shows a new selection labeled View or Span. The
Zoom function is divided into six levels:
• 2X Split—shows two reduced-size sonar pictures at the same
time. The right half of the screen shows the complete sonar
image at its original scale. The left half shows a portion of the
original image at 1/2 depth scale.
• 2X Zoom—shows the full screen image at 2X zoom.
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• 4X Split—shows two reduced images, the right half of the
screen shows at the original depth scale. The left half of the
screen shows 1/4 the original depth scale.
• 4X Zoom—shows the full screen image at 4X zoom.
• Btm (Bottom) Split—shows two reduced-size images. The
right half of the screen shows the original depth scale. The left
side of the screen shows sonar returns. All target depths read
as a distance from the bottom.
• Btm (Bottom) Lock—shows full screen sonar returns from
the bottom up.
TIP: Quickly zoom in and out of the Sonar display by pressing
the IN and OUT keys. Turn off the zoom function by pressing
the OUT key until the No Zoom setting appears.
View/Span—allows you to change the viewing range of a zoomed
display. If the display is 2X or 4X split, only the zoomed portion on
the left side of the screen is affected by the change. If the display is
Bottom Split or Bottom Lock, Span adjusts how far off the bottom
the unit shows data. This option is available when a Zoom scale
other than No Zoom is selected.
Gain—allows you to control the sensitivity of the unit receiver
To see more detail, increase the receiver sensitivity by selecting a
higher gain.
GPSMAP 580/585 Owner's Manual