garmin 5208 --chart plotter tracks

[me00351]

i noticed yesterday that the tracks from previous outings were off by about 50 feet north .
it was easy to confirm since i was in a canal and the old tracks showed up on land.
the only thing that i've done since my last trip is the most recent software update from garmin.
i'll call garmin tomorrow to get their answer.
has anyone had the same experience?

[me00351]

the garmin support folks said to reinstall the software update.
they also said that they've not had other users reporting these kinds of issues with the plotter.

[Birdman]

Couple of things:

1. Did you see /view the track before the software update? Do you know/are you sure it wasn't over land prior to the software update? It's possible the update had nothing to do with it, you just noticed it after the update.

2. What is your track plot frequency or distance set to? If the time frequency or distance is set to far apart (like 10 munites or 1 muile), it would be asy for the track to go over land. For example, lets say you navigate around a small island that is 1/2 mile round. You start on one side, at which time the plotter plot s a point, then you nav aroudn the island (not over the land!) and when on the other side, the plotter plots the 2nd point of your track since you now 1 mile from the original point. It then draws a lione from pt 1 to pt 2, which of course would go straight across the middle of the island. This could be your case.....

3. Sometimes, when they rasterize charts (make them digital), they end up off a little bit in certain area (especially around edges of charts). Since your GPS can be off up to 30' sometimes, and the chart can sometimes be off a little bit, add them together and you may very well be navigating on land, so to speak.