Triton Isis User Manual
Page 153
June 2004 Isis® Sonar User's Manual, Volume1
139
Notes:
• In the example shown in Figure 8-12, the values for Cable Out and
Depth (arrowed), are being received in real time over a serial port. As
these values change, the display updates automatically. The fact that
they appear “grayed out” does not mean that the values are incorrect,
simply that they cannot be changed by the operator.
• Checking the box alongside either Cable Out or Depth allows the
operator to override the automatic value. The operator's entered value
would then be saved into the .XTF file.
• If, for some reason, the Depth value exceeds the Cable Out value
(perhaps a zero from the cable counter due to bad connection, or a
large incorrect depth value due to bad depth sensor) then the Current
Value panel will display ERROR.
• In
Playback
Mode, these values will update in the same way, provided
they were recorded in the .XTF file during the acquisition process.
Layback = sqrt{C
2
- (D-H)
2
}+ O
C= Cable Out, D = Towfish Depth, H = Towpoint Height, and O = Offset
Calculating Layback Using “Percent of Cable Out”
In some cases it may be preferable to have Isis calculate the layback by applying
an operator-entered percentage of cable out. This method would be useful when
there is no depth sensor on the towfish or where the along-track position
difference between known objects on lines running in opposite directions can be
measured directly from a mosaic.
Clicking the radio button alongside Percent of Cable Out changes the dialog
box to that shown in Figure 8-13:
Chapter 8: Using the View Menu