Originally Posted by hpeer
Screen shot of chart plotter. Lets see if this is clear. Presuming it is, you can see my track through the headlands.
But, when using Fugawi
4.5 in split screen
with GE, and doing an overlay, the headlands and harbor line up.
Image is not attaching, says "Rotate Image"
Started to happen a couple of days ago.
Try this PhotoBucket link to the same image.
Francois Bay Photo by hpeer | Photobucket
I don't have Fugawi
and can't comment directly on the coincidence of GE overlayed on the chart.
I'm wondering what would happen if you were to import
the track into GE? I think it would plot right on top of the channel into Francis Bay. This is why I think so; I just plotted the cursor position (from your screen
shot) on OpenCPN
using CM93 charts
. It plots about .5 nm SW of the apparent Fugawi cursor and is about .2NM due East of West point (and lands right on the ferry
track). I mentally moved moved your track .5nm West and a little South and it looks like it might be OK. Which says the CM93 chart might be OK.
I then moved the cursor position to GE and it plotted .2nm East of West point. Which says that for that point CM93 and GE were similar.
Yes, I think you are right.
This is starting to get complicated to explain.
The screen shot is off my Standard ?Horizion CP using CMap.
Apparently CMap used the larger scale chart. I have a paper copy.
The Fugawi raster chart is of a smaller scale, but without the errors. Thus it lined up in Fugawi, but does not have certain detail such as the buoy.
Fugawi actually presents GE side by side with no overlay. The overlay is ONLY at this location and an adjacent harbor. clearly someone has "checked" the accuracy at these two locations.
Due to this exercise I now have a better understanding and I THINK someone checked the charts against GE.
BTW, I went in their in dense fog
. It's a little disconcerting to sail into a headland on your CP. I found the buoy by easing up to it, ( coulda been a rock on radar) that gave me confidence i was in the right crack in the rock, ( they all look the same on radar) then ran in on radar
I had known of the potential for chart errors from reading the paper chart. Had I not, but blindly gone in, things could have been very different.