let me be the first to say 'wow'!  that second image...with the 'shadows' of the fish on the bottom...showing fins...just too cool!

I'm chomping at the bit to get open water and 'on the water' with my new side/downscan...lots to do...

bad part is I may not get to do much fishing!

Just amazing.

So, I'm curious about these "shadows" that show up in a number of the StructureScan pics - espicially those of trees, etc.

Is there something specific that results in the sonar representing this, perhaps due to the lack of signal to represent that area as it was reflected earlier in the water column, OR, is it some really clever signal processing / graphics rendering to create a photo-realistic rendering.  Either way its really amazing, but I was just wondering if anyone had insight into what these 'shadows" really were.....

to visualize this take a flash light and shine it from your transducer to the sides and down.  That is the easiest way to explain it....  Light can't bend around a corner and have a direct hit   Ie drop offs will result in a darker area...  as shown in the picture below on the left side where the rocks are there and the darker area shows up right on the drop..... light can't do a 90 degree bend around a corner and hit it directly  so the shadows are that of the object in the way..  does  that make scence....

yeah - I assumed the "shadow" is effectively where there is no signal return as it was bounced back by something higher in the water column - its just that the shadows off the trees and such look so, so realistic that its hard to believe - pretty amazing technology...