Marking waypoints on 998 screen

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03-26-2011, 06:47 PM
talltimber

Marking waypoints on 998 screen

I marked a waypoint a while back. It was, at the time, about half way down the screen on my 998. I could see a stickup from the brushpile, so I was sure about where it was at. The waypoint was twenty feet or so off the pile. I was wanting to know if anyone else has had this problem, or maybe it was my gps reception at the time. I was in a hollow at the time, and I didn't check my acc. I was wondering, also, if there could be a problem with marking things farther down the screen? Do I need to be marking when it first appears? I have looked at a number of screenshots online and most all of them show the cursor down the screen a bit.
03-26-2011, 08:05 PM
rnvinc

I find that my waypoints are more accurate if I actually mark where the brushpile seems to be touching the bottom of the lake...

Rickie
03-26-2011, 09:00 PM
Allan

+1
03-26-2011, 09:06 PM
Mr Hotspot

The image will always be behind, what is on the leading edge is what you justed passed over, Plus the GPS is not WAAS, it could be off at least 8 to 10 feet. WAAS get you
with in 3 feet. The next day you go, the spot might be right on and the next day off again. It is not that pin point, just use the waypoint to get you to the area and SI to pin point it for each day.
03-27-2011, 07:29 AM
talltimber

Quote:

Originally Posted by rnvinc

I find that my waypoints are more accurate if I actually mark where the brushpile seems to be touching the bottom of the lake...

Rickie

Does it seem to matter where the image is on the screen at the time? Can you tell a difference in accuracy of your marks, in relation to where the images were on your screen when you marked them? Top, middle, bottom, mid to extreme left/right? Does a STOPPED screen hold the proper coord's, somehow, to be able to mark an object after the boat actually travels another 200ft (arbitrary distance) and how accurate is this type of mark? Just a general question, not looking for numbers here. Fairly acc. , not too acc., on the money, :D
03-27-2011, 08:38 PM
rnvinc

Quote:

Originally Posted by talltimber

Does it seem to matter where the image is on the screen at the time? Can you tell a difference in accuracy of your marks, in relation to where the images were on your screen when you marked them? Top, middle, bottom, mid to extreme left/right? Does a STOPPED screen hold the proper coord's, somehow, to be able to mark an object after the boat actually travels another 200ft (arbitrary distance) and how accurate is this type of mark? Just a general question, not looking for numbers here. Fairly acc. , not too acc., on the money, :D

I really don't think it matters how far back on the screen the structure is when you mark it...I can mark structure when it scrolls to the bottom of the screen and still go back and find it...

Also...I can record a section of water...play it back at home...either on the unit or in Humviewer...mark waypoints from the recorded GPS data...and still go back and find the structure...

It will be really close...

Rickie
03-28-2011, 06:03 AM
talltimber

OK, thanks a bunch. I guess I had some reception problems or something in that spot, or that day, whichever. Good to know.
03-28-2011, 10:51 AM
Dray81

If you are in SI mode can't you move the cursor to the point and get an exact coordinate?
03-28-2011, 07:44 PM
talltimber

I don't know, but the mark displayed on my map did not reflect the position of the brushpile that I had marked. I didn't sit on the spot and compare that to the coord's of the waypoint.
03-28-2011, 09:56 PM
rnvinc

Quote:

Originally Posted by talltimber

OK, thanks a bunch. I guess I had some reception problems or something in that spot, or that day, whichever. Good to know.

I've also marked brush (or what I thought was brush) on the SI screen and go back later to find that there is actually nothing there at all....

Disappearing brush..?? phantom echo..?? someone's anchor dragged it away..??

Sometimes...*#@* happens...who knows...??

If I can't refind what I marked before and confirm it with 2d..I either look for it another day or delete it from the unit....

Rickie
03-30-2011, 04:33 PM
Humminbird_Greg

There is some things in your installation setup that can add to a waypoint marked on any of the sonar Views being “off”. First would be if there is anything that can block the signals from the satellite from being directly received (not reflected off of something) by the GPS Receiver. This may mean that you need to mount it above the level of the motor. Another is that the GPS Receiver and transducer are separated by some distance. When you mark a waypoint the unit assumes that the GPS Receiver and transducer are in the same location. If they are eight feet apart (GPS Receiver on the console) than you could be introducing an error of up to 2x that distance (in this case 16 feet), depending on what heading the heading you were on when you marked the waypoint and what heading you are on when you look for it again. Keep in mind that this inaccuracy gets added to the GPS system accuracy.

By the way: if the GPS Receiver can receive the signal from ether WAAS satellite it will use it. The only way to know if you are receiving it or not is to look at the GPS Diagnostic View and see if it is showing “Enhanced” in the “Fix Type” box in the upper right corner of the display.