Navionics Map Off

[Tadpoletodd]

I have a Lowrance GlobalMap 3500 w/ a Navionics Premium Map chip (Premium North). I've noticed the last two times out on the water (different lakes) that the map seems to be off about 50-100 feet. Is this common? Is the chip bad? Is there anyway to correct this? It's extremely frustrating!!! Help!

Thanks

[hanson]

My guess is that you are fishing on a lake that hasn't been accurately mapped yet.

Some of the big lakes like Mille Lacs, Winnibigoshish, Lake Minnetonka, etc have been mapped in incredible detail in the last couple years and the GPS accuracy on these lakes is incredible.

I believe both Lakemaster & Navionics have used DNR maps or something similar to give close contours on the majority of the lakes on the chips. If you are fishing one of these lakes, you could be wayyyyy off.

What lake(s) are you fishing?

I've used my Lakemaster chip many times on the Mississippi River and some of the time, the GPS shows my position on land even though I'm in the channel.

I would have to say that there is nothing wrong with your chip or your GPS.

[Surface Tension]

Just as Hanson said your using data thats not very accurate, as in lake surveys.

[musky hunter]

I have the Navionics chip and have had incredibel accuracy on Mille Lacs. But sometimes, the unit itself is 50-100' off. I know this because of the channel markers in the St. Louis River are accuratly placed by the Coast Guard, and once in a while it will put me in a position on the wrong side of a bouey, about 50-100' off, but that is sporadic, and may be built in to the gps system itself.

[prov1900]

I have a theory that when the "chips" are made, the water levels could be different than what they are at the time you are on the water, therefore resulting in the 50 to 100 feet off thing. Just an idea. I believe this because fishing prominently in the Missouri River basin, during times of drought or high water, my Lowrane 111CHD, you know, the 2K plus fishfinder/GPS, with all the pre loaded data, is way off. For the price, you would think that it would be to the inch, but where I fish, it is far from it. On a side note, when I am playing with my GPS in my driveway, it is to the foot, for the most part.

[Cliff Wagenbach]

I have found with my Lowrance 3200 GPS ( Lowrance/Lake Master chip)that the closer you have the spot zoomed in, the closer you will come to being right-on.

Cliff