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All three cursor positions are meant to be in a straight vertical line from one another on the 2d image...
The results should be the same on any brand....
Someone test it and come back with your results..
Freeze your screen scroll...mark the bottom of the lake....mark straight up in the 2d image somewhere in midwatercolumn...then mark straight up in the 2d image at the surface....
Check the coordinates of the 3 positions...
Then...We will discuss reasons why...
Rickie
The top one is closer to the satellites!
WINNER!
If it wer SI, I would guess #1, because of the whole slant range thing......The waypoint is more accurate when it is at the bottom contact.
In the case of 2D I woud guess #2 because the 2D cone is more narrow at the shallow point of contact on the brushpile.
Change my vote to what bobb said
Surely someone has been fishing so they can try this...:dono
If anyone has a recording handy...just replay it on the unit and make this same test...
Freeze the screen scroll ...and mark the 3 cursor positions...
(It's even the same result in Humviewer on the 2d image)...
Rickie
So this quiz has no answer?
I am no expert on sonar but I do know enough about GPS to know that the signal will not penetrate water. GPS positioning of targets from a sonar unit are the results of sofisticated software corrections and are subject to the accuracy of cursor placement. I would think that closest to the bottom of the targeted return would be the most accurate. It would still be the least accurate to mark from 2D that SI because of the beam and signal configuration.
:hesaid
Yes Grout...there is an answer...I had hoped someone would actually test this on their own unit...Quote:
Originally Posted by GroutScout
The sonar quizzes I offer intend to spark discussion...not just a simple answer and move on to the next quiz...
__________________
Well I guess no one has actually tried this yet...
The 3 cursor positions will have the exact same coordinates...(as long as the 3 cursor positions are in a direct vertical line)...
GPS is the calculations of "longitude", "latitude", and "altitude"...
Chartplotting "Combo" units (units that have sonar and chartplotting)...do not use the "altitude" part of the scenario ....
I guess sonar companies figure if you get the longitude and latitude correct...the structure you marked should be directly under you...
So, it doesn't matter where in the water column you mark a waypoint on the 2d image....as long as yor intended waypoint mark is in direct vertical alignment with the target you are intending to mark...
Rickie
I suppose that a Barometric altimeter,should be considered?