Garmin GPSMAP 420 Owner's Manual page 54

Using Sonar
Zoom—zoom in to a section of the full screen. The zoom is off, or
set to No Zoom by default. Four options are available:
No Zoom—turns zooming off.
•
2x Zoom—twice the magnification.
•
• 4x Zoom—four times the magnification.
• bottom Lock—locks the zoom window to the bottom.
Split Zoom—displays the Split Zoom screen
•
depth Line—quickly reference a specific depth (Show or Hide). To
set the depth of the reference line, select Show, and then press up or
down on the Rocker.
4
(page 45).
GPSMAP 400/500 Series Owner's Manual