Where Down Imaging out performs 2D

[Doug Vahrenberg]

Here is a great example where the Down Imaging and Side Imaging's very narrow - razor thin beam shows more detail than 2D Sonar. Look at these narrow ditches and you can see the depth in Side Imaging and Down Imaging but in 2D sonar the depth is not displayed due to the size of the coverage area. At the depths we are viewing 20° (200 kHz) coverage is approximately 11 foot or 1/3 of depth. Because these ditches are very narrow the 2D sound waves see them as flat - missing the details that Down Imaging and Side Imaging can show.