Lowrance Hook Reveal Series Operator's Manual page 31

Pop-up information
Determines whether basic information for panel items is displayed
when you select the item.
Range rings
The range rings can be used to present the distance from your
vessel to other panel objects.
The range scale is set automatically by the system to suit the panel
scale.
Grid lines
Turns on/off viewing of longitude and latitude grid lines on the
panel.
Waypoints, Routes, Trails
Turns on/off displaying these items on panels.
Course extension line
Turns on/off displaying the Course Over Ground (COG) extension
line on the panel. The COG is based on information from the GPS.
Extension line length
When the course extension option is turned on, specify the length
of the line to be displayed.
SonarChart Live tide correction
When selected, the tide correction feature uses information from
nearby tide stations (if available) to adjust the depth values used by
SonarChart Live as the sonar is recorded.