I have an older GPS with mapping s/w. I have noticed that when I'm out in the boat, the altitude on the GPS will a negative number, [example: -27]. My fish/depth finder, which is not assoicated with the GPS in any way, will have a matching positive number, [example 27]. Is this just coincidence or is my GPS actually picking up the difference between the water's surface and the earth underneath it?
GPS Altitude Question
- Thread starter Flutterby
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