Brunton Pocket Transit Alternatives
George Silver
I have some simple mapmaking I'd like to do this summer and have been
wondering about the simplest tools I might use for short traverses with
some attention paid to determining rough elevations and a few slopes and
inclines.
At first I thought maybe a Brunton Pocket Transit and a plane table might
be the way to go, but now that I have been able to borrow a Brunton, I am
not so sure I'd find it usable.
First off, even though it's the damped model, for someone who's used to
marine handbearing or lensatic compasses it seems near impossible to
steady. Getting all the levels lined up and sighting via the mirror seems
beyond me. In addition, I can't read the bearing off the compass with
any sort of accuracy because of the superfine gradations.
I also find it very difficult to take a steady reading of a slope which I
have confidence in. Again, it seems impossible that anyone can steady a
Brunton and take a reading within 10' (the smallest division on the
vernier for the inclinometer).
My first question is: Is my reaction to the usability of a Brunton
justified or are there many tricks to using them that I need to know? If
so, can anyone recommend a good book?
My second question is: What are the alternatives to a Brunton?
I have seen descriptions on web sites of the Suunto Twin and the Suunto
Tandem. Also some mention of Recta compasses which seem to be liquid
damped and have inclinometers. Silva also seems to make a combination
instrument with compass allegedly readable to 1/2 to 1/3 of a degree and
and an inclinometer of considerable (implied but unspecified) accuracy.
Any thoughts or suggestions will be welcomed with great appreciation.
--George Silver
geo...@earlham.edu
Phil
George:
I believe that then Brunton Pocket Compass is fine for simple mapping.
The trick to performing a compass survey accurately is to use
procedures that build redundancy into your measurements. For
example read your bearings and vertical angles forwards and backwards at
each station; take multiply readings at each station both forwards and
backwards; do a closure calculation on the total survey, analyse your
results and adjust all your measurements accordingly.
I my opinion more skill is involved in doing a compass survey than in
doing a modern day traverse with a Total Station.
I am not sure where you are located. Here in the U.S. there is a book
(pamphlet) that was written by Henry Snipe, entitled "How to get a 1:2000
closure using a compass". The actual title may be somewhat different.
Most sellers of surveying products who sell survey books will have
knowledge of this book. Mr. Snipe (deceased) was nationally know for his
knowledge of compass surveys.
Hope this helps
Phil
Robert F Guba
On Thu, 10 Apr 1997 16:39:20 -0500, geo...@earlham.edu (George
Silver) wrote:
>I have some simple mapmaking I'd like to do this summer and have been
>wondering about the simplest tools I might use for short traverses with
>some attention paid to determining rough elevations and a few slopes and
>inclines.
>
George,
I have found the Tasco Offshore 54 binoculars very useful for simple
surveying. The binoculars have a built in compass with 1 degree
divisions. It also has scales for determining distance and object
size. If held level I imagine one could get rough elevations. I
purchased mine from Cabela's.
Bob Guba
19T 296336 4706643 WGS84
E-Mail: rfg...@ma.ultranet.com
Home Page: http://www.ultranet.com/~rfguba/
jbro...@seanet.com
In article <georges-1004...@ki.cc.earlham.edu>, <geo...@earlham.edu>
writes:
> Path:
>
> At first I thought maybe a Brunton Pocket Transit and a plane table might
> be the way to go, but now that I have been able to borrow a Brunton, I am
> not so sure I'd find it usable.
>
>
> My first question is: Is my reaction to the usability of a Brunton
> justified or are there many tricks to using them that I need to know? If
> so, can anyone recommend a good book?
Bruntons used to be popular for forestry work (probably still are) and I used
to use them a lot for mapping in caves. One thing about cave mapping, however,
is you generally are crawling and you set the compass on a rock or the ground--
in short you need to get it steady to read it well. When standing up, I always
put mine on a camera tripod. A forester friend of mine has a clever little
tripod, in a leather belt case, that has the proper adapter built in. Problem
is, today, the you see Bruntons sold in shops that don't carry the adapter.
If you can steady one, they work pretty well.
Jerry Broadus
J. Luke
George Silver wrote:
>
> I have some simple mapmaking I'd like to do this summer and have been
> wondering about the simplest tools I might use for short traverses with
> some attention paid to determining rough elevations and a few slopes and
> inclines.
>
> geo...@earlham.edu
The Silva Compass with the hinged mirror is good enough to sight within
half of a degree when you practice enough and it is dampened for eazy
use. After setting the declination and with the cord around your neck,
hold the compass level with the mirror at a 30° angle and the line in the
mirror centered over the center of the compass needle. Turn the dial
until the red point of the compass needle is centered in the arrow below.
Open the compass and record the bearing or azimuth of the sighting. The
Suunto Clinometer can be estimated to a quarter of a degree for vertical
angles. I do not like the Brunton either and have won $100 in a bet on
who could run the best line for half a mile (the Brunton lost!). I have
used these tools with much success to run mining claim and timber sale
boundaries as well as for recon of section lines and section corners.
--James H. Luke, PLS
--Denver, Colorado
lu...@eazy.net
Bob
In article <georges-1004...@ki.cc.earlham.edu>,
geo...@earlham.edu says...
]
]I have some simple mapmaking I'd like to do this summer and have been
]wondering about the simplest tools I might use for short traverses with
]some attention paid to determining rough elevations and a few slopes and
]inclines.
]At first I thought maybe a Brunton Pocket Transit and a plane table
]be the way to go, but now that I have been able to borrow a Brunton, I
am
]not so sure I'd find it usable.
There exists a British book by Frank Debenham, "Map Making", that covers
everything you asked about. It gives plenty of detail about compass
surveys and simple planetabling, including making your own gear! The
book should be available through interlibrary loan. I use a planetable
for 80% of my map work because I can see the map AND the ground at the
same time.
Good luck!
Bob :{)
Kent McMillan
In article <georges-1004...@ki.cc.earlham.edu>, geo...@earlham.edu (George Silver) says:
>
>My second question is: What are the alternatives to a Brunton?
>
designed for mounting on a jacob's staff. If you are to be
traversing in an area that has enough soil to stick a staff into,
the Warren-Knight may be worth looking at. They are a bit more
expensive than the Brunton, but for the extra money you get:
(a) tall sight vanes that make sighting along even inclined lines
quick and easy,
(b) a gradient/vertical angle scale for the sight vanes,
(c) a 3-1/2 in. needle in a circle graduated in bearing angles and
azimuths, easily read by estimation to less than 10 minutes,
I use my W-K staff compass mainly for running trial lines and for
reconnaissance, but have also used it for traversing
riparian meander lines between conventionally surveyed control points,
lines where inaccuracies of 0.5 ft. in position are of little
consequence but getting a good mapping of a sinuous line would be
extremely time-consuming by any other method.
Forestry Suppliers used to sell this compass, but I am no longer
on their mailing list and so cannot say whether it is still in
their catalogue.
regards,
Kent McMillan, RPLS
Austin TX
Ralph Massie
In article <5ispt7$9...@news.whidbey.com>, Bob <?@?.?> writes
>In article <georges-1004...@ki.cc.earlham.edu>,
This info is available as a package, c/w templates for kit, somewhere on
the net. My apologies for not being able to remember where.
--
Ralph Massie
Aneberie Techtonics
Technology and the Art of Construction
Dean Osgood
In article <5iqjn9$ieh$1...@news.ime.net>
Phil <ph...@ime.net> writes:
> I am not sure where you are located. Here in the U.S. there is a book
> (pamphlet) that was written by Henry Snipe, entitled "How to get a 1:2000
> closure using a compass". The actual title may be somewhat different.
> Most sellers of surveying products who sell survey books will have
> knowledge of this book. Mr. Snipe (deceased) was nationally know for his
> knowledge of compass surveys.
F. Henry Sipe (WV RLS #1) was a delightful gentleman who worked out of
Elkins WV. I mgot to meet him in 198?2 and learned more in one
afternoon about compass surveying than I had in many years prior(I am
haveing trouble remembering the exact title of his book, but I belive
it was titled or subtitled "Compass Land Surveying, a technique for
low-value property surveys" or something, and my copy is 300 miles
away.) I would contact the West Virginia Association of Land
Surveysors for information on his book if everything else fails.
As to the Suunto and the Warren-Knight, the Warren-Knight can work
down to an arc minute of angle, the Sunto will only work to 1/10 of a
degree or 6 minutes. However the Sunto is considerably less costly and
far more rugged. It depends on the accuracy you need
Dean Osgood
Sara McMillan
In article <5j8be5$f...@post.gsfc.nasa.gov>, dos...@proxima.gsfc.nasa.gov (Dean Osgood) says:
>
>haveing trouble remembering the exact title of his book, but I belive
>it was titled or subtitled "Compass Land Surveying, a technique for
>low-value property surveys" or something,
The full title of the book is:
"Compass Land Surveying, A Guide for surveyors, attorneys, landowners and
others", F. Henry Sipe, McClain Printing Company, 1979. It is indeed a
great book on compass surveying and is generally a very down-to-earth
account of surveying in rural West Virginia that is the perfect antidote
to an overdose of high technology.
>As to the Suunto and the Warren-Knight, the Warren-Knight can work
>down to an arc minute of angle,
I think you have in mind the top-quality compass
that Warren-Knight makes, the Sipe-Sumner Vernier Compass. It does indeed
have a one-minute vernier on it and is an excellent, but rather expensive,
instrument. Warren-Knight also makes lesser compasses, including a Forester's
Compass, that are not so costly.
Regards,