SailNet Community - View Single Post - BVI chart/nav app
View Single Post
Old 12-28-2012
TakeFive's Avatar
TakeFive TakeFive is offline
Proud "picnic sailor"
Join Date: Oct 2009
Location: Swarthmore, PA
Posts: 2,886
Thanks: 6
Thanked 72 Times in 64 Posts
Rep Power: 6
TakeFive will become famous soon enough
Re: BVI chart/nav app

Originally Posted by fallard View Post
If you use the Imray-Iolare charts, note that they are not only not to NGA standards, but they are on a different datum than the US charts and your chartplotter, which is undoubtedly on WGS84. Read the fine print on the chart if you want to be precise, although there is only a very slight correction if you want to transfer a waypoint from the chart to your GPS.
In my tests with the chartplotter programs, I was concerned about both datum and projection (though the latter not such a big issue close to the equator), so I carefully verified both. The NGA chart header says it is WGS datum, and the NOAA chart is as well.

I will heed your warning to watch out for the datum on any charts that are on the charter vessel. Are there simple offsets available?

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Formerly posted as "RhythmDoctor"
1998 Catalina 250WK Take Five (at Anchorage Marina, Essington, on the Delaware River)
1991 15' Trophy (Lake Wallenpaupack)
1985 14' Phantom (Lake Wallenpaupack)
Reply With Quote Share with Facebook