Humminbird Side Imaging Forums
Side Imaging Forums => 798c SI => Topic started by: bobxxx on April 24, 2012, 08:57:03 PM
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I have a lake I need to offset when I go to it. after coming from another lake and it gets to be a pain.I was playing around with a recording and noticed my tracking wasn't where it should have been.During the recording ,I waited until the Icon got by a good reference point and went thru the offset procedure and presto,every thing came into line.I haven't been back on the water but if it holds true,it would be allot easier to set up the offset before I get on the lake.
take it for what its worth.no guarantee's
Bob
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Yep it does happen. Wish it didn't.
Remember that maps have the disclaimer that says do not use this as your primary means of navigation..
Chuck
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Bob,
Just remember that when setting the Map Offset men that you are effectively moving the map and not adjusting the coordinates. It is like you are aligning a picture of the lake to some known point or feature.
I recommend setting a waypoint on each lake that you have to use the Map Offset feature on. The waypoint should mark some easily identifiable feature on the map so setting it will be quick and easy. Example: Mark a waypoint at a favorite boat ramp. Before launching; power on the unit and allow the GPS to come up and than align the boat ramp on the map with your map offset waypoint.
Be aware too that some lakes are actually multiple maps all tied together. An offset to the map in one area of the lake may make another area of the same lake (which is actually another map) show off.
As more and more lakes are newly mapped, the need for the Map Offset menu will go away…
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thanks for the info guys,I'll heed your comments.there all good.
Bob
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I was just wandering,does it make any difference that the reference point I use is one I created in googlee of a bridge abutment and transferred into my unit
Thanks in advance
Bob
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No, the origin of the waypoint does not matter as long as it is a known physical location and can also be found on the map data.
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One thing to keep in mind on lon/lat is the datum used to derive the position.
To have a point be comparable it must be in the same datum.
Otherwise it will have some offset. (physical different spot)
Datams are those things you see in setup menus like WGS83 or WGS84 Or Nads27. If you look thru then possible selection there are about 150 datums worldwide.
Mostly the US uses WGS or NADS.
Chuck