Opencpn Charts out of alignment

[MannyEA]

Hi Team,

Just started using opencpn as I am currently refiting a 50 year old sail boat I have just purchased. I have downloaded chats from ocharts and have notice the charts are not aligned correctly.

please see attachment

Cheers,

Manny

[cagney]

The problem is not with OpenCPN. You have a detailed plan of 1:8000 inserted within a smaller scale chart of 1:90.000. The larger scale chart is of course more detailed and is probably based on a later and more detailed survey.
The discrepancy of the 5 m contour is because the charts are different, as issued by the AUS Hydrographic office.
This is quite common around the world when HOs are splicing together charts originating from different surveys made at widely different times using increasingly better survey equipment.
In this case, sand drift may also be factor.

Thomas

[MannyEA]

Hi Thomas

Thankyou very much for the information on the charts, much thanks,

Regards

Manny