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(no email)
Date: Sun Aug 06 2006 - 02:37:58 EDT
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
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