side image question 2024
phenom880 reply :
so i understand that the tree in the center of picture is in about 20 fow and should be right under the boat since it spit the image..How ever if i was to move that curse, to the left to the base of the tree it would say 20 feet to the left of the boat...now if i was to move the cursor 5 feet further to the left it would say 25 feet to the left but wouldn't it really just be 5 feet from the tree that is right under my boat? This is something i have never understood with side image...someone help?
Logan S reply :
I'm not a super expert, but I've always assumed that these types of things are a result of the sonar cones.
J Francho reply :
Think of the image "folded. Directly under the boat is that dark spot, or middle (/) of what I typed below. The sides are the flat. You're in 20" water, so the tree occupies that 20' wide footprint in the (/). If *I* were to mark the point, I'd use the DI if I wanted the most accuracy.
SI is like this:
/
_____/ T_____
The T is you basically your tree. The owner's manual is probably a better bet for a perfect explanation.
Team9nine reply :
Believe it would depend on how they are calculating cursor position, and what true SI coverage is. I've seen suggestions that the split J Francho diagramed above doesn't really exist on some units. They might also be calculating distance from transducer (angular measure or additive measure) as opposed to horizontal distance from boat or centerline. A little more time on the water and a few marker buoys would get you an answer next trip out ????
Tennessee Boy reply :
Based on what you are saying and what I'm seeing in the picture, I think it has to be the distance from the transducer. On my Humminbird, that would be the case. Team9nine brings up an interesting issue of the split or width of the V in J Francho's diagram. Is it wide like this _/_ or narrow or non existent like this _|_ ? On your picture, it clearly exist because you have the herring school in the water column on the left only. If it did not exist then the water column on both sides would be the same. I hope your user's manual gives more information than mine on how wide this is. It makes a difference in how you interpret what you see.
J Francho reply :
I'm going by the documentation for my pre Mega Helix.
It's probably narrower than my diagram, somewhere between yours and mine?
Maybe this will help? the bait is below and to both sides, all the way to the surface.
phenom880 reply :
then would you agree edge of the school to the right is roughly 24 ft away at its furthest point ?
J Francho reply :
Yes, and in fact, here's some video as I approach:
Team9nine reply :
The discussion on the coverage split is interesting because nearly every manufacturer shows the coverage split as depicted by J Francho, but some curious anglers have produced enough anecdotal evidence to suggest otherwise. In the OP's screenshot above, if you only look super close at the tree and the fish marking in its branches, both sides (images) appear to be practically the same, right down to branches and individual fish location among them. If there is a true "black hole" beneath the boat as manufacturers often depict, how could this (the image above) be? My guess is that in ideal settings/conditions, there is no "black hole." Ideally, we'd need something smaller but easily identifiable (perhaps a cinder block) to see if you could get even small objects to split onscreen. Doing so would suggest coverage overlap.
Tennessee Boy reply :
Very interesting discussion. So let say you are in 20ft water and you pass is a large fish to the right side. The fish is 5ft deep and 18ft from the transducer. Where would the fish appear on the screen? On my Humminbird Solix I think it would appear in the water column on the right and would appear to be 18ft deep.
phenom880 reply :
jfrancho let me ask you this then....if i sank a 10 foot telephone pole vertical in lake bed and the actual location was 10 feet to your left in this picture how would it show up?
J Francho reply :
On 8/21/2018 at 11:15 PM, phenom880 said:jfrancho let me ask you this then....if i sank a 10 foot telephone pole vertical in lake bed and the actual location was 10 feet to your left in this picture how would it show up?
Really good question! Very close to this spot are a set of submerged dock pilings. Some are straight, some are crooked. The straight ones should work just like your telephone pole test case. The water is really green right now, so this will be a good test of my ability to read the returns. I'll try to get some shots next time I'm out on "The City Dump."
phenom880 reply :
So in red i circled what looks to be smaller rocks the boat went right over because they show up split on both sides......the blue marker is supposed to be a 10 foot telephone pole ...you can tell depth because its roughly half way up the water column....how far away from the boat to the left is it? If it is 22 feet away like the cursor would tell you then where is all the information from 22 ft to right under the boat where the rocks are?
phenom880 reply :
On 8/21/2018 at 11:14 PM, Tennessee Boy said:Very interesting discussion. So let say you are in 20ft water and you pass is a large fish to the right side. The fish is 5ft deep and 18ft from the transducer. Where would the fish appear on the screen? On my Humminbird Solix I think it would appear in the water column on the right and would appear to be 18ft deep.
what if said fish was 18 feet deep and 5 foot from transducer...i think it would show in the same spot
Tennessee Boy reply :
On 8/22/2018 at 12:10 AM, phenom880 said:what if said fish was 18 feet deep and 5 foot from transducer...i think it would show in the same spot
The fish would appear in the same spot as long as it was on the right side of the boat and 18ft from the transducer as if you measured this distance with a tape measure from the fish to the transducer. So it could be 18 ft deep and almost directly below the boat, it could be 18ft out to the side of the boat and almost at the surface of the water, or somewhere in between.
My unit allows you to remove the water column and this is suppose to give you the horizontal distance to an object on the screen and not the angular distance (direct distance from the transducer). I use this setting most of the time.
Team9nine reply :
On 8/21/2018 at 11:14 PM, Tennessee Boy said:Very interesting discussion. So let say you are in 20ft water and you pass is a large fish to the right side. The fish is 5ft deep and 18ft from the transducer. Where would the fish appear on the screen? On my Humminbird Solix I think it would appear in the water column on the right and would appear to be 18ft deep.
I would agree...depth shown is distance from transducer, which is why you can mark fish that appear to be deeper than the water depth you're in.
mattkenzer reply :
I am getting a headache but this topic is extremely interesting.
Thanks for sharing.
Team9nine reply :
On 8/21/2018 at 11:46 PM, phenom880 said:
So in red i circled what looks to be smaller rocks the boat went right over because they show up split on both sides......the blue marker is supposed to be a 10 foot telephone pole ...you can tell depth because its roughly half way up the water column....how far away from the boat to the left is it? If it is 22 feet away like the cursor would tell you then where is all the information from 22 ft to right under the boat where the rocks are?
Can't say for certain since you added it to the picture but it doesn't really exist. If it was in the actual screenshot, you would use its shadow to help tell height and location, as well as its base as a reference point along with which side of screen it showed up on.
phenom880 reply :
thats a good point with the shadow ...i need an actual screen shot of something tall coming off the bottom that only shows on one side
Todd2 reply :
It's no wonder I don't catch fish, I need to bring along an abacus to figure them out.????
phenom880 reply :
k...here is a post from another site on the same question i asked..
Correct ... Targets directly under the boat will show in both left SI and right SI ...
Distance to targets in SI (out to the side) is calculated as "slant range" to targets ... (that geometry Pythagorean thing) ...
mattkenzer reply :
It was just a matter of time before Pythagoras got involved.
phenom880 reply :
On 8/22/2018 at 12:58 AM, mattkenzer said:It was just a matter of time before Pythagoras got involved.
ahahaha so true.....But it seems distance to side is not measured horizontally like i thought...so if i move my cursor
over to a brush pile and it says 34 feet its not 34 feet across the top of the water when im sitting in my boat. if i was in 22.1 FOW it would be 25.8 feet horizontally .....i think ahahahahaha
Team9nine reply :
On 8/22/2018 at 12:56 AM, phenom880 said:k...here is a post from another site on the same question i asked..
Correct ... Targets directly under the boat will show in both left SI and right SI ...
Distance to targets in SI (out to the side) is calculated as "slant range" to targets ... (that geometry Pythagorean thing) ...
Sounds like it confirms the "no dead zone" theory and we can ignore the split cone diagrams they all like to show ????
A-Jay reply :
Just drop a way point on it and turn around.
A-Jay
Team9nine reply :
On 8/22/2018 at 1:06 AM, phenom880 said:ahahaha so true.....But it seems distance to side is not measured horizontally like i thought...so if i move my cursor
over to a brush pile and it says 34 feet its not 34 feet across the top of the water when im sitting in my boat. if i was in 22.1 FOW it would be 25.8 feet horizontally .....i think ahahahahaha
Yep...
mattkenzer reply :
On 8/22/2018 at 1:06 AM, phenom880 said:ahahaha so true.....But it seems distance to side is not measured horizontally like i thought...so if i move my cursor
over to a brush pile and it says 34 feet its not 34 feet across the top of the water when im sitting in my boat. if i was in 22.1 FOW it would be 25.8 feet horizontally .....i think ahahahahaha
If the cursor is measuring the slant then your math is correct.
J Francho reply :
On 8/22/2018 at 1:09 AM, Team9nine said:Sounds like it confirms the "no dead zone" theory and we can ignore the split cone diagrams they all like to show ????
That's how I feel. Kind of changing how I'm imagining what I'm seeing on the graph.
phenom880 reply :
On 8/22/2018 at 1:13 AM, J Francho said:That's how I feel. Kind of changing how I'm imagining what I'm seeing on the graph.
you have no idea how long this has been bothering me lol so glad we "got to the bottom" of this.....see what i did there? lol
J Francho reply :
I still want to go by those old pylons. Never marked them because you could always just see them. Now that the water is higher by a couple feet, and green, can't see them.
12poundbass reply :
Tennessee Boy reply :
On 8/22/2018 at 12:58 AM, mattkenzer said:It was just a matter of time before Pythagoras got involved.
The history books tell us that Pythagoras first used his discovery to reestablish property lines in the Nile Valley after floods. I think we all know that what he was really doing was calculating the position of structure and cover before the flood so that he could fish it during the flood.
mattkenzer reply :
On 8/22/2018 at 1:43 AM, Tennessee Boy said:The history books tell us that Pythagoras first used his discovery to reestablish property lines in the Nile Valley after floods. I think we all know that what he was really doing was calculating the position of structure and cover before the flood so that he could fish it during the flood.
Just spit my Iced Tea at my computer screen .... 
12poundbass reply :
On 8/22/2018 at 1:43 AM, Tennessee Boy said:The history books tell us that Pythagoras first used his discovery to reestablish property lines in the Nile Valley after floods. I think we all know that what he was really doing was calculating the position of structure and cover before the flood so that he could fish it during the flood.
That was pretty funny!
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