Thread: Sonar Quiz #22

Originally Posted by Redge

Rnvinc I liked Slabbacks answer of the pea gravel, do you know what the bottom actually was?
Thanks I learned something new!
Good questions Kosmo, looking forward to the DI answer.

The image I used was a stock Humminbird image ...so I wouldn't know the actual bottom composition ...

Rickie

Originally Posted by kosmo

Can a person, using di, tell the bottom hardness?????

I would say "somewhat"...

In the image below (also from Doug) ...we can definately see in the DI image the same "brightness" of the harder bottom that is seen in the SI image ...



1 point to remember in the above image is this is "DI from SI" ...which is the same data - just rearranged in the DI image ...

Rickie

Thanks rnvinc, I don't use 2d much, maybe 1% of the time. I liked the pea gravel, because it had the thin red line on the top of bottom. I really appreciate the quiz posts. Sometimes I can't ask the question, because I don't even know what I don't know!!
That's as clear as a silt bottom! LOL

I would have expected the thin red line to change to a lighter color at the transition ( B1 ) Learn something new everyday.............

I believe you can tell the difference between hard and soft bottoms on DI. I know you can see when it changes.

Originally Posted by kosmo

Can a person, using di, tell the bottom hardness?????

Sure can but you must have your contrast set correctly or you will bloom it out and not be able to discern the difference.
I try to keep my contrast set about 70% unless I'm real shallow. (Lowrance HDS)

rnvinc here are two shots for you. This first one I know to have peegravel due to using a jigging spoon and coming up with small gravel in the hooks when I let it hit the bottom and jerk it back up. Also I use break rotors from a truck as a anchor and have small chunks stuck in the grooves.






In this shot it's a compacted mud flat...the anchor comes up with a cloud of gunk lol. This was the reasoning for the earlier post in reference to the peegravel. I have a lake that is shell rock and should have some shots in 2D in one of these files. When I find one I'll post it as well. The RED line is much thicker in those shots.

Found one. (look over the writing, it's from a earlier post) This bottom is shelf rock that drops off.






Can anyone see the sediment build up and why would it be there?