[Coral-List] Mapping procedure

wahszel wahszelee at pd.jaring.my
Fri Aug 8 03:43:43 EDT 2003

Dear Marianne,

Greetings!  I have been mapping shallow and patch reefs in Malaysia and
Borneo using the RoxAnn Seabed Classification System since 1996.  I started
with general habitat mapping; and managed work my way to discriminate the
reefs down to growth form types.  I am also doing the accuracy assessment
for such mapping method.

The system I used could record position, depth, seabed (growth form) type
and others simultaneously every second.  These logged data can be exported
to Surfer(TM) directly (without having to enter them manually) after field

>From my experience, it is hard to maneuver the boat and produce 'good'
transect lines if I use a boat smaller than 20ft.  Not only the wind and
wave would caused a snake-like transect line; the pitch and roll will also
affect the accuracy of the sonar readings.  Traveling speed is very crucial
too to ensure good quality data.

Wish you all the best for your work.


Wah Sze

----- Original Message -----
From: "Marianne Gilbert" <marianne2 at ekno.com>
To: <coral-list at coral.aoml.noaa.gov>
Sent: Friday, August 08, 2003 5:10 AM
Subject: [Coral-List] Mapping procedure

> Hi fellow listers,
> I am looking for anyone who has a good procedure for mapping shallow
> coral reefs using GPS and single-beam sonar.  We are trying to
> roughly map depth profiles of reefs around Samoa.  We have an Eagle
> Seacharter that can record both depth profiles and GPS coordinates.
> We are planning to enter the data into MapInfo.
> It would be a lot easier/cheaper for us if we can do this using
> Polynesian canoes instead of a motor boat.  I tried mounting the
> probe on a canoe and it works but wind and currents can be a problem
> when trying to travel in straight lines...  Any advice from people
> who did similar things would be greatly appreciated!
> Thank you!
> Marianne
> Marianne Gilbert
>  ><>
>         <>><
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