Sorry, I've been away.
To answer questions, the GPX route was created in OpenCPN
and exported. When reimported, those routes were off. However, the problem is not appearing since the original two GPX routes were exported. I can create a route now and reimport the route, and it is exactly on the correct points on the map. Actually, export and import
was working properly even before I re-downloaded the maps again from NOAA.
This leads me to guess this was not an improperly calibrated chart, but a runtime aberration where the map to GPS
, or route to GPS
somehow became corrupted.
Another poster mentioned a behavior where the routes seemed to shift when scaling and zooming the map. I don't recall
that specifically, but perhaps there is a bug. The best practice would be for OpenCPN
to give a runtime error if it became aware of a disconnect between map / GPS / route waypoints - but that is a big "if".
It is working for me now, and I've manually recreated the routes. But my confidence level and concern is that there may be a bug which is not evident if a route is made at sea, at night, etc.
I don't think I've saved the bad GPX file. But I'm not sure it would help much. In my browser it appeared well formed, it loaded without error, and it was repeatable. It didn't look any different from my replacement other than the GPS coordinates being off. Most of my waypoints were exactly on government
buoys so it was easy to notice the errors, and they were all off by about 1/4 mile in the same direction. It was much further than a zooming resolution, pixel click, error.
If I see this again, I will report back. It would be great to know if the routes somehow get offset. Perhaps a good work around for now would be to export, exit the OpenCPN, re-open OpenCPN, import
route and visually verify.
Thanks to all for your attention.