SailNet Community - View Single Post - Gps navigation advise
View Single Post
post #9 of Old 12-12-2012
Senior Member
Join Date: Dec 2010
Posts: 5,111
Thanks: 1
Thanked 227 Times in 187 Posts
Rep Power: 7
Re: Gps navigation advise

Originally Posted by chucklesR View Post
Paper charts are invariably out of date - I use them for planing, the make great table top discussion / conversation pieces, not so much for actual underway plotting.
How are your electronic charts more accurate than the properly-updated government paper equivalent they are based upon?

Or, is Navionics now doing their own surveys of the world's waters, now? Goggle Maps and satellite imaging are now calculating water depths, as well?

Originally Posted by travlineasy View Post

A great example of this was discovered when I was traveling down the Intra-Coastal Waterway a few months ago. The GPS Plotter showed I was cruising on dry ground, at least 150 feet outside the waterway, but within a margin area delineated by a dotted line. I called a friend at USGS about this and he provided me with the details. Essentially, the chart was created prior to the construction of the ICW in that area. Consequently, the location revealed by the GPS/Plotter was accurate, but the charts portrayed where the proposed ICW was - not the actual location where it was eventually dredged.
Gary, if your plotter put you on dry land anywhere along The Ditch, something is very wrong, whatever charts or apps you're using are piss-poor... Such a thing can indeed happen in many places, but in using my the C-Maps my own Simrad and many other units use, and a variety of other e-charts I've used, they've always been pretty much spot-on for the entire length of the ICW... I've been placed in the wrong lane on the NYS Thruway, or on the wrong side of the railroad tracks along the Erie Canal, for instance - but I've never been placed on dry land anywhere along the US East coast, that I can remember...

Something's very wrong with your setup, that simply shouldn't be happening in the location you describe... I find it inconceivable that any modern e-charting software would be using information/surveys that pre-date the actual creation of the ICW...
JonEisberg is offline  
Quote Share with Facebook
For the best viewing experience please update your browser to Google Chrome