Humminbird LCR 3D - Manual (Page 20)

Pressing the VIEW button again will display the unique Quad-Beam® view in which all
four beams are displayed side by side on-screen. This is similar using four different depth
sounders simultaneously, with the sensors aimed in different directions. Pressing the VIEW
button again will return you to the 3D view.
Three sizes of fish symbols are used to depict fish.
Structure or thermoclines are shown with individual pixels or groups of pixels.
ID "ties" the fish to the bottom beneath it for location in the 3D view.
A Word About Fish Size...
The size of the fish symbol used to depict fish is based on the sonar return strength of
that fish regardless of it's depth or position relative to your boat. This is called "normalizing". The
size of the fish symbol represents the relative strength of return for that fish, which is often a good
indicator of fish size, but different species of fish have different sonar characteristics.