JCSM Shareware Collection 1996 September/JCSM Shareware Collection (JCS Distribution) (September 1996).ISO/bother__/sly253a.zip/siy11.txt

Text File | 1995-03-03 | 18KB | 399 lines

 SIY11.TXT   Helpful Hints for Surveying in the Real World     59


                           Chapter 11


          Helpful Hints for Surveying in the Real World


In this chapter you will read tales of hard-won experience.  Many
of these inspirations have come while surveying in some deep dark
dank dripping muddy hole in the ground.  This surveying method
was devised to give usable data under the worst of environmental
conditions.  Cheaply.  With inexperienced assistants, or no
assistance at all.  The instruments are practically
indestructible under abnormal use.

The only simple way to destroy a Silva Ranger compass is to put
it on the dashboard of your car or truck.  The defroster will
cook it.  The plastic mirror will craze and warp and the compass
capsule might get an air bubble in it.  Silva warns, "Do not lay
your compass near [a] radiator[,] or where [the] temperature can
become excessive, such as on a pavement in the sun." I have never
tried a radiator, but I have defrosted a couple of Rangers.  I
don't spend much time around pavements or in The Sun, but I never
have had any trouble with sunshine, black rocks, and the Ranger.

I also once broke the hinge on a Silva Ranger by dropping it on a
sidewalk.  I have dropped Rangers on rocks hundreds of times
without damage, but the one time that I dropped one on a sidewalk
was fatal.  Stay away from sidewalks!

The basic surveying method is so simple that I have seldom spent
more than an hour teaching someone to survey in a cave.  The
worst problem is getting legible notes.  It takes about ten
minutes to master the mysteries of the compass.

If the compass is tilted, then it will give you the wrong
answer.  Be sure that the needle jiggles when you tap the
compass.  Look in the mirror to check this.  Don't try to look at
the compass dial directly.

The best way to improve the quality of your survey is to improve
the quality of your compass readings.  Be sure that you have
taken a good compass bearing, then take another one.  Or better
yet, take backsights too.  Best yet, have your assistant use a
different compass to take the backsights.



 SIY11.TXT   Helpful Hints for Surveying in the Real World    60


The compass declination changes with time, as much as a degree
per decade.  The declination map in the Silva instructions is
sufficient for most surveying.  If you have a declination error,
it will result in the map being rotated.  This is more of a
nuisance than a calamity.  When you are comparing maps, just
rotate for best fit.  The amount of rotation is the declination
error and can be measured with the protractor.  A new map could
be plotted or calculated with the correct declination if you
think it is worth the bother.

Magnetic declination is shown on the topo map of the area.  The
Isogonic Chart of the United States (see Chapter 14) can also be
used to calculate the current magnetic declination.  Why bother?
The chart in the Silva Ranger Instruction Manual is a bit dated,
but is still plenty good enuf for surveying it yourself.

If you have a modem, then you can call the USGS Branch of Global
Seismology and Geomagnetism.  This is a US Government computer,
so it has some odd parameters.  Set your modem for 300 or 1200,
7, S, 1.  The toll-free number is 800-358-2663.  When you finally
get to the main menu, select M for Geomagnetic Field Values
(GEOMAG).  There is a helpfile available.  You will need to know
the latitude, longitude, elevation, and date for which you wish
to know the magnetic declination.

The tape measure must seem like a new kind of candy to animals.
I have had one tape measure devoured by a herd of pigs, and
another damaged by a dog.

The 200 foot fiberglass tape measure can make quite a Gordian
Knot if you aren't careful.  My suggestion is to coil it up
around your elbow and hand.  Tie it with a piece of twine.  When
uncoiling, walk away while feeding tape from the same side of the
coil from which you wound it, Last In First Out [LIFO].

On ground flat and smooth enuf to walk easily, a compass and pace
survey is the ultimate in getting a lot of information for a
little trouble.  The 10% error is acceptable for much preliminary
work.  If I have an assistant to keep the owner occupied, I can
usually pace survey while walking around the land the first time.







 SIY11.TXT   Helpful Hints for Surveying in the Real World    61


Try to pick survey stations which you can find again.  Not every
station need be permanent, but do it whenever convenient.  A
gatepost, an unusual tree, a point of rock, or a piece of pipe
pounded into the ground are good permanent stations.  Flagging
ribbon or rags will make a station more obvious.  Temporary
stations need be no more than a scuff mark.  If you blaze trees
or make other permanent marks, be sure that they are in the right
place first.  Especially if they are on someone else's land!

A 300 foot roll of bright orange flagging ribbon is available
from CAVE, Inc for two bux [$2] + $1 shipping & handling.  Other
colors, stripes, polka dots, and flags on wire are available
special order.

When permanently marking property lines, it is considered to be
in good form to invite the affected neighbor along.  Bring your
camera too.  If it ever comes before twelve of your peers, then
photographs will be worth a lot more than some mumbo jumbo about
compass error.

You need not make the distance between stations the same as did
the original surveyor.  He probably set as few stations as
possible.  It takes the boss about ten minutes of fiddling to get
a good set with a transit or undamped forester's compass.  Then
he can relax while the rest of the crew hacks brush for a half
hour.

The Silva Ranger uses no tripod and takes only ten seconds to
read.  I usually read the compass at each tape-length.  You can
set up long shots to reduce the number of compass readings, but
it is certainly not worth it.

The clinometer should be read parallel to the ground.  This means
that your target should be your eyelevel on your assistant.  The
tape measure should be read parallel to the ground too.  The tape
should be pulled tight, with just a little sag.  And don't go
around a tree and put a bend in the tape.

If your station is a mark on the ground and you hold the tape at
waist height, then you must read the tape over the station mark.
Drop a pebble or your pencil from the supposed tape reading and
marvel at how far off you can be.  It takes a lot of tape error
to have much effect on your survey, but since this is a
systematic error (all in the same way) you should eliminate it.



 SIY11.TXT   Helpful Hints for Surveying in the Real World    62


You don't need to occupy exactly a station to use it.  Here in
backwoods Kentucky, corners are commonly trees.  It is rather
difficult to stand at the center of a tree!  Unless, of course,
the tree is long ago dead and rotted away.  But then you can't
find it.  [You can't win.  You can't break even.  You can't even
get out of the game.  (That's thermodynamics for you!)]

But you can measure as if you were measuring to the center of the
tree.  Sight the compass on the center of the TO tree while
standing in front of the FROM tree.  Measure the TAPE to halfway
around the tree.  Have your assistant put the clinometer target
at the proper height alongside of the tree.  Another handy trick
is for both you and your assistant to take a step or few to the
side.  This could enable you to "see thru" some brush, or to get
away from a perturbing fence or hornets' nest.

If you are trying to follow another surveyor, you must be able to
find at least one of his stations.  It need not be the starting
corner.  Just a station which you can identify.  You can start
anywhere and go in either direction.

If you cannot find any previous station, map the given boundaries
of the parcel.  The resulting map should look pretty much like
the map drawn from the land description in the deed.  The
boundary should be made of segments which intersect at the
corners.  From the comparison, you should be able to come close
enuf to find an indication of the corner if there is anything
there to find.

Just because your predecessor was a professional surveyor, don't
assume that he couldn't make a mistake.  While most of today's
surveyors check their work for blunders just like you should do,
it wasn't always so.  There are occasional blunders.  Typograhpic
errors, they call 'em.

The old surveys here in the far Boonies of Kentucky are overrun
with blunders.  Many were surveyed from the safety and comfort of
the owner's front porch, with the assistance of a jug or three of
moonshine.  It is quite possible for you to be right and for
everyone else to be wrong.  It is quite common, actually.

Even if the old surveyor did a good job, there are copying
errors.  I have noticed that about one new mutation is made for
every three deed transcriptions.



 SIY11.TXT   Helpful Hints for Surveying in the Real World    63


Every station must reference a previous station, or be a fresh
start.  But FROM need not be THE previous station, only A
previous station.  You can go back and branch off from any
previous station.  When branching, circle the FROM in your notes
so that you will be sure to notice it when plotting.  You can
shoot many stations from a single station, such as the locations
of several buildings.

It is possible to have multiple loops in your survey.  These
often help to isolate a blunder to a particular part of the
survey.  When calculating closure, remember that RUN is the
distance around the loop in question, not necessarily the entire
distance of the survey.  For instance, you could map the
boundaries, plus the roads, trails, fence lines, streams,
buildings, wells, and cave entrances, as well as any other lines
and points of interest.

You need not actually put your assistant on a station to survey
it.  A "compass and guess" station is often sufficient.  You will
get good at guessing the tape after a while.

A station can also be located with compass directions from two
other stations, and no distances.  Measure and plot the
directions from the other stations.  Your inaccessible station is
where the direction lines cross.

You probably won't want to survey right down a line such as a
fence or the middle of a river.  The fence perturbs the compass;
the river perturbs the surveyor.  Simply survey alongside the
line and measure the offset.  Five paces is a good distance from
a wire fence.  Be sure to record which way to the fence, as well
as how far.

It is a simple matter to survey around a hornets' nest or a briar
patch.  Just keep good notes of what you are doing.  You may want
to plot field map as you go along.

If you are trying to survey a straight boundary between two
corners, you needn't concern yourself with surveying a straight
line.  Survey wherever convenient, plot this line on your map,
draw your straight line, measure the offset at each intermediate
station, and go back to the field and move your tentative
stations as indicated.  It sounds overly complicated, but it
really is a lot easier done this way.  Use a similar technique to
subdivide out a specific acreage.  Plot a map, survey in the
field, repeat until satisfied.

 SIY11.TXT   Helpful Hints for Surveying in the Real World    64


A good next book up is "Compass Land Surveying" by F. Henry
Sipe.  See Chapter 14, Sources.  This book is full of useful
information without a lot of fancy mathematics.  The instrument
used is the Forester Compass, but most of it is applicable to the
Silva Ranger.  There are good chapters on the legal aspects of
surveying and on problem solving.  Sipe is showing you how to
think about what you are doing; he is not training you to recite
magic formulae and incantations.  A good next book down is "A
Layman's Guide to Land Surveying" also by Sipe.  Here he explains
how to hire the right surveyor and how to tell him what you want
done.

In general, when land is sold, the intent of the seller, rather
than the actual land description, takes precedence.  It is just
too easy to blunder when surveying or typing.

The locations of the corners control the location of the boundary
lines.  A fence may stray from the straight line between corners,
but that does not automatically make the fence line the boundary
line.  Of course the adjoining landowners may agree to call the
boundary line any place they choose.  If this agreed boundary
line is much different from the prescribed location, a written
contract should be executed.  Consult your attorney.  If a line
is marked and remains uncontested for a number of years (which
varies from state to state), then there are grounds for adverse
possession.

The direction and distance are merely an aid to finding the next
corner.  The actual location of the corner takes precedence over
where the "degrees and poles" run to.  If no one has blundered,
then you should be close enuf to easily find whatever the corner
is.  Blazed trees, carved rocks, car axles or pipe pounded into
the ground, and cast concrete posts are good ways to mark corners
so that they may be easily found.

Corners or lines which move, such as a trail junction or a stream
bed, may or may not move the property corner or line.  The
general rule is that if the movement is evolutionary [insidious,
gradual, and progressive], the boundary moves also.  If the
movement is revolutionary [obvious, sudden, and catastrophic],
then the boundary does not move.

|\__/|
\ O.O|
 =(_)=
     Oh WOW! You brought me a mouse.

 SIY11.TXT   Helpful Hints for Surveying in the Real World    65


If you have any problems in applying the basic surveying method
to your particular situation, ask.  Draw a sketch of what you
want to do.  I'm especially interested in any scientific
applications.  This is a good method for measuring points, lines,
areas, or volumes with dimensions ranging from a few tens of feet
to a few miles.  The expected error is about 1% of the distance.
A mile of survey line should take between about an hour and a day
to complete with a two or three man crew.  Applications range
from the exotic to the mundane.  My particular uses are mapping
caves, locating property boundaries, and setting farm building
foundations.

I can't tell you everything about everything.  Before you holler
for help, THINK about what you are trying to do.  If you want to
modify the method, then you should calculate how this would
affect the final survey.  Draw yourself pictures whenever you get
stuck.

And when you are stuck good, it will not be because of something
which you don't know, but rather it will be because of something
which you do know that ain't so.

There are situations when a 1/2 fast survey simply is not good
enuf.  For disputes, or where a licensed surveyor is mandated by
force of law, get a professional.  Even then, you probably will
want to survey it yourself first.  Get all the problems solved
and the arguments with the neighbors settled before the $100 an
hour fellow arrives.  You can also keep licensed surveyors
honest.

You should agree with the professionals within your limits of
error.  If not, then don't stop asking questions until you know
the reason why.  And don't accept magic as a answer.  Magic is
for magicians and shysters and such.  Magic will get you ripped
off.

The hand plotting method with the Silva Ranger compass works well
only when the tape distances on the map are between 0.5 and 3
inches.  If you are using a two hundred foot tape measure, you
cannot accurately plot on an aerial photo or topo map scale.


____/|
\ o.o|
 =(_)=
   U     Save me from these newfangled mice!

 SIY11.TXT   Helpful Hints for Surveying in the Real World    66


You can accurately reduce a larger map on graph paper by the
method of squares.  Select your reduction factor, such as ten
times smaller.  Draw big squares on your map, with each side of
the big square the reduction factor [10x] squares long.  Now
sketch your new map on the small squares, using the map with the
big squares as a guide.  Enlargements are done the same way, only
different.  Of course, if you have calculated, rather than
plotted with a compass, then you can plot directly at any scale.
And if you use my CAVEMAP program on your computer, it might even
draw the map on your printer.  An enlarging/reducing copier can
also be used, but it probably won't be able to make the scale
which you want.

If you have the proper sort of mentality, you can see that you
could easily prestidigitate a few numbers in a land description,
and no one would be any wiser.  At least not until after the land
was magically stolen, and then it is too late.  You can see that
you don't need to actually walk down a boundary line to survey
it.  You would use a calculator to be sure that everything closes
perfectly, with no embarrassing closure errors to attract
suspicion.

Even if you don't have this sort of mentality, others do.  People
have been thinking this way for at least 3500 years.  Moses had
something to say about it in his second book of rules for
maintaining a civilized society.  See Deuteronomy 19:14 & 27:17.

If any of this is still magic after you have practiced a few
times (except for the fact that the red end of the compass needle
points North) ask me for a better explanation.  No magic.  When
you make blunders in magic, you can't catch them.  This makes
magic very dangerous.  There should be no magic in your
surveying.  Magic is for magicians and investment advisors.

Copyright (c)1995 by David Perry Beiter

If you have any questions, problems, or comments, write or call
me.
Dave Beiter, CAVE Inc, 1/2 Fast Road, Ritner KY 42639.
606/376-3137.
MCI Mail: 635-1762
[e-mail]
X.400: c=US;a=MCI;s=BEITER;d=id=6351762
CIS: >MCIMAIL 635-1762 (be sure to include your name in the text)