Humminbird 515 Operation Manual page 8

Bot t om Pr esen ta tion
Bot t om Pr esen ta tion
As the boat moves, the unit charts the changes in depth on the display to create a profile
of the Bottom Contour. The type of bottom can be determined from the return charted
on the display. A Hard Bottom such as compacted sediment or flat rock appears as a
thinner line across the display. A Soft Bottom such as mud or sand appears as a thicker
line across the display. Rocky Bottoms have a broken, random appearance.
Bottom Contour Profile with
RTS® Window. Temp/Speed
Accessory is optional.
Hard Bottom
Rocky Bottom
The sonar returns from the bottom, structure and fish can be represented as either
Inverse (default), WhiteLine®, Structure ID®, or Bottom Black. See Sonar X-Press
Menu: Bottom View for details on how to set the bottom view.
Inverse is a method where weak returns are shown
with dark pixels and strong returns with lighter
pixels. This has the benefit of ensuring that weak
signals will be clearly visible on the display.
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Soft Bottom
Structure ID® represents weak returns as light
pixels and strong returns as dark pixels. This has the
benefit of ensuring that strong returns will be
clearly visible on the display.
WhiteLine® highlights the strongest sonar returns
in white resulting in a distinctive outline. This
has the benefit of clearly defining the bottom on
the display.
Bottom Black displays all pixels below the bottom
contour as black, regardless of signal strength.
This has the benefit of providing a high contrast
between the bottom and other sonar returns on
the display. Any targets such as fish, structure
and thermoclines will be shown using the Structure
ID method.
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