Next message: Arild Jensen: "RE: lv-ab: Vector Charts"
I used C-map on a standard horizon chart plotter
and proved to be extremely accurate to the buoy next to me.
Although in a couple of occasions in Richelieu river it was of to land for a
minute or two
other than that if I did not have it there was no way to navigate north end
of lake Champlain in
total darkness and water level very high that the buoys were submerged and
not visible.
Along with a good depth instrument I made it through the rocks and shoals
chewing on parts of my soul.
I don't mean to say that it is to be used as primary navigation tool. Paper
charts are the primary
source of information and navigation. "BUT" when you don't have them
available because of short in money
and changing circumstances it is an invaluable tool.
Yanni Marinated
S/V Princess Thalia
Hamilton
www.yannismarine.ca
----- Original Message -----
From: <>
To: "LIVE_ABOARD" <>
Sent: Sunday, August 06, 2006 2:37 AM
Subject: lv-ab: Vector Charts
> Hi All,
> On another list the message below was posted.
> This was my response.
>
> And once again I am reinforced in my negative
> opinion of vector charts. The problem is all too
> obvious, human beings can NOT be trusted to make
> decisions regarding the accuracy of the charts we
> are offered. The 'official' paper charts are
> already bad enough (datums that are not accurate,
> GPS not used to make them, ridiculously old data,
> etc.) but when yet another human (the people
> making the vector charting decisions) gets in
> between the paper charts and the navigator it is
> just not safe.
> Oh well, I'm sure I will get all sorts of flame
> over this one... :-)
>
> Eric Thompson
> S/V Procrastinator
> South San Francisco
>
>
> ORIGINAL POST:
> I recently had a chance to play with a Furuno
> Navnet system while planning a
> trip from Vancouver to Campbell River upcoast on
> Vancouver Island.
> This stretch is part of the waters used by a lot
> of people travelling from
> Washington state to Alaska.
> Furuno Navnet uses the C-Map vectorcharts.
>
> While trying to set up the system and also dp some
> route planning, I noticed
> a number of discrepancies which really shook my
> confidence in using C-Map
> for any serious navigation.
>
> To begin with the vessel location was placed a
> considerable distance inland
> on some zoom levels. Thsi tells me that the
> geo-referenceing of the chart
> data used by C-Map is not consisitent nor is it
> accurate enough.
> Trying to find the destination marina in Campbell
> River revealed additional
> discrepancies. The level of detail shown and the
> manner of presenting the
> shore lines and depth contours wsa not confidence
> inspiring.
> What would normally be a curved line had distinct
> points connected by
> straight lines.
> This come from not using sufficent points when
> digitizing the area to begin
> with. Although some details wer showsn regarding
> nav aids etc. the manner
> in which rocks and other natural hazards were
> depicted did not seem to be
> sufficient.
> When I had a chance to compare the C-MAP
> electronic cartography and the
> official paper charts produced by CHS the poor
> quality of the C-Map system
> was clearly evident. Personally I would not trust
> the Navnet system using
> C-MAp cartography to navigate these weaters.
> To say I was disappointed is an understatement.
> Likewise the Furuno radar
> display with soft keys and multi layered menus
> proved to be a PITA to set up
> and use. While the professional Captain was
> struggling with trying to get
> the darn nav system working to his satisfaction I
> was compelled to point out
> approaching traffic which posed a hazard or
> potential collision. The thought
> crossed my mind that if we both got too involved
> in configuring the Navnet
> we just might end up in an accident with another
> boat.
> We eventually returned to dock while I continued
> to fiddle with the
> electronics trying to get it to work. Meantime the
> professional Captain
> drove into town and bought a full set of paper
> charts for the trip planning.
>
> regards
> Arild
>
>
> ___________________________________________________________________________
> || The Live-Aboard List : send a "subscribe" or "unsubscribe" request
> ||
> || in body of message to:
> ||
>
>
___________________________________________________________________________
|| The Live-Aboard List : send a "subscribe" or "unsubscribe" request ||
|| in body of message to: ||
