Humminbird 500 series, 515 manual

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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