Manual

June 2004 Isis® Sonar User's Manual, Volume 2 79
Isis takes a contact’s measurements in the following order: width before
length before height. (Isis uses these distances along with towfish position,
towfish attitude and sonar beam width to calculate the contact position and
size.) Accordingly, you mensurate your contact in width-length-height order.
To mensurate a contact’s width
1. Position your trackball’s pointer at the left or right edge of the
contact.
2. Hold down the left trackball button and rotate the trackball to draw a
line across the contact’s width (across track).
3. Release the left button when you have completed the line.
4. Target displays a magenta line spanning the contact’s width.
A
lways measure the width of a contact before measuring the width of the contact
shadow.
To mensurate a contact’s length
1. Position your trackball’s pointer at the top or bottom edge of the
contact.
2. Hold down the left trackball button and rotate the trackball to draw a
line through the contact’s length (along track).
3. Release the left button when you have completed the line.
4. Target displays a magenta line spanning the contact’s length.
To mensurate a contact’s height when a shadow is present
1. Find the contact’s shadow.
2. Observe and position your trackball’s pointer at the left or right edge
of the shadow.
Appendix E: Using the Target Utility