Quote:
Originally Posted by hellosailor
Bob, could that have been chart datum error? GPS and Admiralty charts using different chart datums? Or GPS and radar not being set to use the same display, i.e. DD.MM.mm versus DD.MM.SS perhaps? |
The datum (WGS84 vs. NAD27, for example) usually only makes a couple hundred feet difference, and the electronic chart "informs" the chart plotter of its datum. The
radar and
GPS were set correctly, as they aligned properly before and after visiting the Mariatas with no change in settings. Also, the land was where the
GPS claimed it was before and after visiting the Marietas.
If you compare the
charts (electronic and otherwise) with Rains's Mexico Guide, you can see that there is a difference in the lat/lon between the two.