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2.16
How to Compare Concentration of School of
Fish
2.16.1
How to compare with the fish estimate mark
You can get an estimate of the volume of two schools of fish by using the two ESTI-
MATE keys as follows:
1. Operate the trackball to place the cursor on a school of fish, and then press the
ESTIMATE 1 key.
The estimate mark 1 appears on the school of fish. Relative volume is shown by
a figure between 0 and 100, below the estimate mark. When the area inside the
mark is filled in reddish brown, volume figure is said to be 100. When the estimate
mark is entered, a graph is shown at the histogram on the numeric/graphic data
display.
2. Operate the trackball to place the cursor on another school of fish, and then press
the ESTIMATE 2 key.
Compare estimate figures for each school of fish by observing estimate mark data
and the fish histogram.
3. To turn off the estimate marks press their respective keys.
25
25
Note: The fish school mark and event mark 1 can be entered with the fish estimate
mark. For details, contact your dealer.
Fish histogram
The fish histogram shows, in graph form, signal strength distribution for the school(s)
of fish marked with an estimate mark on the horizontal/slant displays. The histogram
display for each of those displays will be different since the calculation method is dif-
ferent. This data appears only when an estimate mark is active. When two estimate
marks are active, histograms are displayed one on top of the other as below.
The horizontal axis shows signal strength in 16 colors, and the vertical axis shows the
concentration of a school of fish inside the fish estimate mark. For the fish estimate
mark inscribed on the horizontal display (or slant display) the graph shows the aver-
age movement in five scans, to increase accuracy.
1
1
E
Estimate mark 1
1
N
North mark
R
Relative fish volume
ume
2. HORIZONTAL MODE
2
2
Estimate mark 2
65
65
2-29
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