Hello!
Considering all the questions related to environmental + money factors,
could someone advise me on the best GPS to be used in tropical
rain forests?

Thank you in advance,
Alexandra Krause

................................

E. Alexandra K. Krause
Universidade Federal do Para' - Brazil
kra...@marajo.secom.ufpa.br

In article <199611251911.OAA58...@atlanta.american.edu>, Elke Alexandra

I do not know what you want to do with your GPS locater. I used a Garmin
GPS in Peru and Southern Chile to obtain latitude and longitude and
Universal Time Coordinates. It uses 4 AA batteries, weighs about 8 oz and
is easy to carry and use. It is also very rugged and reliable and costs
around US $300.00 which won't bankrupt nyone. You can get a PC cable and a
boat mount. I understand the coordinates are accurate to 30 meters. The
altitude, however, often seemed to have a large error margin.

 It was developed, primarily as a navigation aid for boaters, and hunters
which would be perfect for the rivers of the selva. You mark and store
waypoints into a number of routs and guide yourself with by steering (or
walking) the compass heading. I draws a little path on a small screen and
gives you distance speed and estimated time of arrival. It beeps when you
get close to a waypoint. It is perfect for locating points in a very
changeable landscape. You need an open space to acquire satellites fixes
to obtain your coordinates. It is simple and straightforward.

I got mine through a mail order firm for boating equipment Outer Banks
1800-682-2225. There are various models from ~$150 to $650. for a model
with a built in VHF radio.

Hope this helps.

--

On Mon, 25 Nov 1996, Elke Alexandra Klever Krause wrote:

Please post response, or at least copy to me - I'd be interested.

--
Wolfgang Wuster
School of Biological Sciences, University of Wales, Bangor, UK
e-mail: w.wus...@bangor.ac.uk

Thought for the day: If you see a light at the end of the tunnel,
it is probably a train coming your way.

Hello!

I would like to thank all people that sent me advise on GPS for tropical
rain forests. It seems that the big problem is always the vegetation
interference (sih...) The suggestions to overcome it were mainly "extensions
of the antenna", "use of amplifiers between the antenna and the unit", and
"use of units that have multiple receivers". Apart from, of course,
"climbing trees/hills" and "deforestation"... ;)

I would also like to share with you the address of the newsgroup related
to GPS <sci.geo.satellite-nav> that Tom Davis kindly sent to me.

Alexandra

............................

E. Alexandra K. Krause
Universidade Federal do Para'- Brazil
kra...@marajo.secom.ufpa.br

In article <199611251911.OAA58...@atlanta.american.edu>,
   Elke Alexandra Klever Krause <kra...@marajo.ufpa.br> wrote:

I used GPS briefly in old-growth and mature red fir stands in northeastern
California, U.S.  I didn't get good enough reception from satellites to get
accurate location data, due to the heavy canopy cover.  If you can choose
where you place GPS receivers, choose areas with sparse overhead canopy cover
(perhaps a clearing, road, ridge or mountaintop), unless you have the
resources to build supports for your GPS receivers which rise above the canopy
cover or can place them in trees.  Avoid placing receivers at the bottom of
ravines or gorges.  My understanding is that Trimble Navigation Corp. is
considered the best U.S. based company for quality, selection, and price of
GPS equipment.  Receivers can be as inexpensive as $600.  The best choice of
GPS depends on the application you use it for, though: animal tracking, road
mapping, benchmarks, and boundary mapping all have different optimal
equipment.  
  If you can't choose where GPS receivers are placed, be warned that you may
not get usable location data in areas with high percent canopy cover, and may
need to use a backup method.
Hope this helps
L.Ellis
Graduate Student
Dept. of Wildlife
Humboldt State U.
Arcata CA U.S.A

Elke Alexandra Klever Krause wrote:

As a theoretical physicist working on complex systems, and the tropical
forest being one of current topics of interest, I have the great
pleasure to spend a month or so every year in the rainforest (especially
French Guyana); my experience with GPS is that you CAN NOT RELY ON THEM;
we have tried different models, and the conclusion is that the cheapest
(e.g. Garmin 38) are as good as others. Only in very open clearings you
get enough signal to get a position. They are not useful under a decent
canopy.

Nevertheless, I have heard there was one, developped in Brazil for the
army; you might check that as you are from Brazil: I would be very
interested to have more information on this myself.

Yours

Marc A. Dubois