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The
following is an excerpt from a review of
The Contour Professional Data Collection Module
by Kevin Falvey
Boating Magazine, September 2001.
Once you're wired for soundings, making your own chart is
simple. Go to the area you want to survey, start the
program, and click the "record" icon. Begin a
series of mowing-the-lawn-pattern runs over the area. As you
are recording, watch the screen. In addition to seeing your
boat's icon move across the display, you'll see
lollipop-shaped icons being dropped along your course. It's
as though you're planting a tree every few seconds,
outlining both your course and the contour of the bottom.
The more "trees" you plant, the more accurate the
chart you will produce.
Your boat's speed, the water's depth, the update speed of
your electronics, and how you re-set Contour Professional
all affect accuracy. A faster-updating GPS and sounder
coupled with a slower boat speed in shallower water allow
for the best accuracy. We charted the oyster reefs at 3mph,
with Contour Professional's update rate set at five seconds
in less than 20' of water.
Once your system is hooked up make some dry runs to see what
gives you the best accuracy. What's accurate? That depends.
A cruiser looking to safely transit a poorly charted area
need only define a fairway over which to run safely. A
fisherman may want to see every nook and cranny of a reef.
When you're done collecting the data, simply follow the
self-prompting commands and save it to a file. You can log
on to the Internet and e-mail the data to Maptech. Or you
can save the data to disc and mail it to them. Upon receipt,
Maptech checks the position and time/date stamp that Contour
Professional imbeds on your data, correlates it to the
nearest tide station, and corrects your depths accordingly.
Turnaround time is three days. It's like mail-order film
developing.
What you get back is a data file that includes [custom]
three-dimensional bottom contour charts. You can print these
to make hard copies. But the best use is onscreen aboard
your boat. [Using Contour Professional with Offshore
Navigator and a 2-D Maptech Digital chart,] you can overlay
the conventional chart with the three-dimensional one and
watch your boat move along the soundings you've collected.
It's the ultimate in confident navigation. There's even a
"search light" function that allows you to see
ahead of your course. This is displayed in cross section in
a small window at the top of your screen. Any area shallower
than your boat's draft is displayed in red.
Out of the box, Contour Professional includes a database,
compiled from NOAA soundings, military surveys, and other
sources, making it a solid conventional chartplotter even
before you add in your own soundings.
Still, you should always proceed slowly into unknown areas,
preferably on a rising tide and watching your sounder as you
go. After you've recorded the data and have your personal
chart in hand and onscreen, you'll be able to return to the
area with confidence and precision. Although the beauty of
Contour Professional is that it allows you to gather highly
detailed information about small, tricky-to-navigate areas,
remember that most bottoms are continually changing and
remain potentially dangerous even after you've charted them.
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