Newsgroup sci.engr.surveying 3682

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Gord McGuire's questions about differences between US and Canadian surveying
practices interest me as well.  This newsgroup provides a remarkable perspective
upon one's own surveying practice through the differences in how we all appear to
go about what are at root the same activities.  I assume that the legal principles
in Canadian and US jurisdictions have all evolved out of the English common law
and that the main legal differences spring from statutory and case law 
particular to our respective provinces/states/territories.
H o u s e   t i e   q u e s t i o n :
As I understood the case that Gord mentioned, the fact situation was roughly as
follows: a surveyor is retracing parcel boundaries in a subdivision in which few or
no monuments of the original survey exist. (A very typical case that describes nearly
all residential subdivisions dating from 1839 to about 1915 or 1920 in Austin, Texas
where I practice.)  Old improvements such as buildings and sidewalks exist that are
either known to have been built nearly contemporaneously with the original
subdivision survey, or are reasonably thought to have been built at a time when
considerably more evidence of the original survey existed than presently can be
found.  The distances from those improvements to lot boundaries as found by prior
surveys are given on old plans either prepared soon after the original survey or
long enough ago that one may think them either (a) to have been made when 
considerably more evidence of the original was available or (b) to represent a
condition long recognized and accepted by adjacent owners (i.e. the plan of a parcel
shows a relation of improvements to a boundary that is essentially harmonious with
the plan of the adjacent parcel) and there is no obvious gross inequity in that.
Gord was interested to know how a prudent US land surveyor might use this extrinsic
evidence of parcel boundaries.
R e g i o n a l   d i f f e r e n c e s :
I may be greatly mistaken, but I would think that surveying practices in the US
differ a good bit among the following regions:
1. Original colonial Eastern states
2. Early rectangular survey states (say, before the Civil War?)
3. Texas
4. Louisiana
5. Late rectangular survey states
6. Urban West coast
My hypothesis is that the nature of the original surveys in these different regions,
and the problems characteristic of them, has shaped land survey retracement generally
in each distinct region.
I will only attempt to relate what I know of practice in Texas and hope that other
colleagues will describe their own regions if in fact the distinction is meaningful.
T e x a s   p r a c t i c e :
In Texas practice our first intent is to dig up the best evidence obtainable of
where lines and corners were actually originally located upon the ground by the
original surveyor of the property we are retracing.  Old improvements are routinely
considered to constitute such evidence, especially in an addition where no surveyor
has ever claimed to have discovered an original corner monument at any time in the
last hundred years or so.  Texas law likewise places great value upon repose.  As 
the passage of time obliterates the original evidence by which a line or corner
might otherwise be proven, more weight is reasonably given to extrinsic evidence.
This is especially the case when such evidence is in harmony with other settled
possessions and when to disregard that evidence would for no good reason upset
boundaries long supposed to be correct by many interested parties.  The logic behind
this is in part based upon the fact that very many old subdivisions were not well
surveyed originally.
In my own practice we only rarely have old plans of surveys showing the distances
of buildings to boundaries.  The only maps recorded in the public records are 
usually the original subdivision plats.  Before 1920 or so, many surveyors gave their
clients the original tracings of their maps and so the maps have not been preserved
as useful private archives.  Even the quasi-public archives of the City Engineer date
only to about 1910 in my city and though often extremely useful are not extensive.
While we seldom have the advantage of recorded plans of later surveys, in very 
confused situations I have nonetheless found it productive to examine trial lines
run at some presumed original offset to structures such as walls and houses.  
Directing the search for evidence by these means is so often productive that even 
when evidence is scant and given two more or less plausible locations for a boundary
line, I would tend to prefer the location in better harmony with old improvements.
The probative weight that one tends to assign to improvements in the case where much
evidence of the original survey exists is different.  This is especially true when
the major weight of the evidence is so inconsistent with improvements that the 
assumption of mistake in location of improvements is warranted.  I have not 
understood this other case to be the one that Gord McGuire was asking about, though.
Canadian colleagues note: tomorrow's high should be 70deg F (21deg C). I'm trying
to recall the last winter that it snowed here.
Kent McMillan, RPLS
Austin TX

In article <3290BB0E.2E9@chau.demon.co.uk>, Michael  says:
> 
>        I am writting a paper for " Gravity - its Relevance and Role in Surveying"
>        Any suggestion and comments are most wellcome.
>        Thank you.
>
Michael:
In case you haven't finished your paper, let me add a couple of suggestions for
ways in which gravity is relevant to surveying.
I think that you could argue that at least two everyday effects of the Earth's
gravity have driven the development of surveying since antiquity:
- water runs downhill, and
- thrown objects travel in curving flight paths.
The construction of irrigation canals, aqueducts, water piping systems, and canals 
for transport were important projects that consumed lots of time, energy, and money
of earlier societies.  The need to have useful information so that the final
products of these ventures actually worked drove the development of surveying
technology.  I suspect that the design of 19th century canals was what required the 
great refinement in the levelling instruments and techniques that was accomplished
then.  If it were not for the flow of water, why would anyone have ever cared what
the relative differences in elevation across a county or a country were?
If you were to trace the sequence of events that has led to the present GPS 
technology that is the big surveying news of our times, surely the curving flight
paths of artillery shells is where you might begin.  Accurate use of artillery 
pieces requires three dimensional maps. Because of gravity, the flight of a shell
fired from a gun of known characteristics is more or less predictable if 
you know the distance to the target and its difference in elevation. 
The military use of maps resulted in the organized training of surveyors,
culminating in the middle of this century in tremendous amounts of money being spent
to devise better ways of lobbing ballistic missiles transcontinental distances 
through the gravity field.  The problem of measuring the separations between launch
sites and targets, and of modelling the gravity field between them is what one
might argue drove the development of modern geodesy culminating in the Global
Positioning System that happens also to be good for a number of other purposes.
Good luck!
Kent McMillan, RPLS
Austin TX

PEUPLE FRANCOPHONE, S'IL TE PLAIT, AVANCE SUR CE SITE !!!
EXCUSEZ MOI MAIS JE NE CONNAIS UN MOT EN LANGUAGE ANGLAIS !!!
MERCI A L'AVANCE.
-- 
Ugo CAPPELLETTI, geometra
Via Scita, 5
32032 FELTRE (BL) ITALY
Tel ++39 (+439) 89373
Fax ++39 (+439) 840290
mercurio@sunrise.it
http://www.comune.feltre.bl.it

Christopher Stevens wrote:
> 
> I recently purchased at auction a transit.  It was identified by the
> auctioneer as a navigational instrument, but my one semester of
> surveying leads me to believe it is a transit.  The only identifying
> marks are the words "Stanley" and "London" stamped into the base.
> 
> Is anyone familiar with this company?  Are they still in business?  Do
> they have a web site?  Do you have their address?
> 
> Any information you can provide is appreciated.
> 
> Thanks, Christopher Stevens
> 
> (ctsteve@ix.netcom.com)
You might want to check this out with David St. John, Benchmark 
Instruments, 317 Maple Street, Franklin, MA 02038; 508/528-7427.
Another spurce of information is the Surveyors Historical Society, 300 W. 
High Street, Lawrenceburg, IN 47025; 812/537-2000.
Ed Miller
P.O.B.

In article ,
   rls2222@internetland.net (Sam King) wrote:
>I have always believed that angles should be "wrapped", as a check in 
the field, against errors, as well 
>as, obtaining a higher degree of accuracy. I also shoot all of my first 
>shots, with the data collector, but take hard notes, as well.
[snip]
>those shots to be taken. Does anyone else traverse this way?  Does 
>anyone else have any ideas for fast and efficient traversing?
When I first began using a data collector I found it too cumbersome for 
control traversing, so used a field book instead and relegated the data 
collector to topo shots.  As my level of comfort increased, I abandoned 
that practice, and now record all traverse data with the data collector. 
(This is in spite of the fact that the TDS routine for multiple angles 
requires BS-FS-BS-FS rather than BS-FS-FS-BS, a particularly annoying 
"feature.")  
The value of having all the data in a single digital file outweighs the 
disadvantage of being able to quickly view the individual measurements, 
and I have come to trust the data collector to warn me about 
unacceptable measurements.
---------------------------------------------------------------------
Jim Frame   jhframe@dcn.davis.ca.us    (916) 756-8584  756-8201 (FAX)
Frame Surveying & Mapping         609 A Street        Davis, CA 95616
-----------------------< Davis Community Network >-------------------

The California Land Surveyor Association has a new web site located at
http://www.pacific.net/~clsa. This is a temporary address until web site is
"published". The "published" site address will be
http://www.ca-surveyors.com.
Frank C. Demling Jr.
PLS

Tyler Parsons (parsont@peak.org) wrote:
: In article , n9649893@scooter.cc.wwu.edu says...
: >
: Now, if I can just figure out why a half-full can of paint which worked
: yesterday, won't work today. Not the nozzle! It has no pressure left.
This is because spray paint has a tube from the nozzle end to near the
bottom of the can.  When you turn it upside down extra propellent is
getting out as the level of paint in the can goes down below the end
of the tube.  I seem to remember from my survey tech days that ther
are companies that produce spray paint cans that are designed to work
upside down.  Of cource that was ten years ago so any names have
slipped from the cranial storage unit.
Rod
: Tyler Parsons, pls
: parsont@peak.org

In article , Stuart Dawson  says:
>
>        I remember reading a paragraph in an old Brit. colonial survey
>manual on how to repair theodolite crosshairs. It began: "First, catch a
>medium sized-spider".
Stuart:
Crosshair repair on old instruments is an interesting business here in 
the US.  I don't know about colonial Africa, but here the finest, most 
suitable, spider silk comes from poisonous black widow spiders. 
I would think that the broken vial on your father's level could probably
be replaced without great expense.  You just need to find a repair shop 
that has been in business long enough to have some suitable vials in
in stock.  Removing the old vial and resetting the new are should be
not at all difficult.
Good luck!
Kent McMillan, RPLS
Austin TX

Here in Washington I have found a few old subdivisions which are best retraced 
by running lines in relation to old house foundations, old rock walls, etc.  
There is an appellate court case in this state accepting the method (called by 
the judges the "rule of possession").  In one particularly difficult old 
subdivision we traced the title to all the lots in a block and also the 
building permits until we found which houses dated back to close to the date of 
the original plat, around some of those we found old sandstone walls of a type 
of construction we found, from expert opinion, had not been used since about 10 
years newer than the plat.  Using those walls for a starting point, we finally 
found the monuments that were shown on the plat but which others hadn't found 
for 40 years.  The idea that old construction can sometimes best show the 
original lot lines is valid, but I feel the burden of proof is on the shoulder 
of the surveyor using such lines.  These are not $100 lot surveys!
Jerry Broadus

rls2222@internetland.net (Sam King) wrote:
> I have always believed that angles should be "wrapped",
> as a check in the field, against errors, as well as,
> obtaining a higher degree of accuracy. I also shoot all
> of my first shots, with the data collector, but take hard
> notes, as well. Then, I "plunge" the scope, and measure
> another set of angles. I find, that many times, the
> rodman will shift, or not quite be plumb yet, at the time
> the shot is taken.  I prefer to let the EDM read continuous,
> observing several distances, as a check, before I write the
> distance down.  If I solely used the data collector, which
> takes only one reading per shot, then I would introduce 
> distance errors, into my field data. The data collector file,
> then comes in handy, when a number was written down wrong,
> in the hard notes.  Yes, I am aware that the data collector
> can record a variety of angle turning methods, and take
> multiple distance shots, if you re-run an entire cycle, but
> I'm in the business to make a living, and I don't have time
> to spend two or three times as long, waiting for all of 
> those shots to be taken. Does anyone else traverse this way?
> Does anyone else have any ideas for fast and efficient
> traversing?  Thank you for your input.
Please keep in mind that I am writing based on my own
limited experiences.
I believe that most instruments have settings that allow you
to specify the number of distance readings taken for each
shot before the average distance is displayed or
transmitted.  This setting may be in the form of a simple
"coarse" or "fine" switch.  I generally use coarse mode for
non-control work and fine mode for critical measurements.
The coarse mode usually completes the shots in half the time
for fine mode shots and is great for general topo and
planimetric shots.  I am quite satisfied with either setting
as far as the desired accuracy of my measurements.
Since I always double for traverse legs and other important
observations, I measure the distance both direct and reverse
and let the data collector inform me of the difference
between the two (or more) shots.  The amount of time
required to take the reversed distance measurement is
minimal (a few seconds).  I even have the option of deleting
the offensive observation from the averaged measurements if
a blunder has been discovered.
A great majority of the time, the difference in distance
measurements are not enough to warrant further shots.
Although there are rare occations when the distance error
warrants at least one additional measurement, I find that I
have to take additional observations to tighten angular
accuracy more often than to correct distance for a jittery
rodman.
I also used both methods of recording observations
(hand-written and data collector) when I first acquired a
data collector.  Now that I have modified my surveying
methods to conform with the quirks of using a data
collector, I only use hand written notes for sketches and
other important notes not readily entered into the data
collector.  I am quite pleased with the traversing
efficiency my data collector has allowed me to achieve.  The
note keeper (usually me) is no longer the time efficency
bottleneck in my field surveys.
Any proven practical method of traversing is acceptable
regardless of the technology used.  The most important
aspect is that the surveyor in charge understand the method
used, and is satisfied it provides the accuracies required
for the project.
--
Bryan Bunch
bwbunch@skn.net
--

In article , jbroadus@seanet.com says:
> 
>of construction we found, from expert opinion, had not been used since about 10 
>years newer than the plat.  Using those walls for a starting point, we finally 
>found the monuments that were shown on the plat but which others hadn't found 
>for 40 years.  The idea that old construction can sometimes best show the 
>original lot lines is valid, but I feel the burden of proof is on the shoulder 
>of the surveyor using such lines.
Jerry, this is an interesting example.
As a point of clarification, in the example you cite what was the rationale given by
the Washington court for the "rule of possession" stated by them and how far afield
did they have to reach for authority of prior case law?   
Also, how old was the subdivision and what sort of original monumentation was
recovered?  Do you encounter in practice many subdivision plats that are essentially
diagrams missing many of the usual elements such as bearings, distances, and even
reference to actual survey?
I am thinking that the retracement of old boundaries is a problem that tends to
change fundamentally in professional practice depending upon the quality of the 
original work.  That is, a subdivision originally marked with pine lumber
stakes and evidently without professional skill would not seem to admit either (a)
the possibility of recovering any original corners 100 years later or (b) using
plainly faulty survey data to accomplish anything other than run out theoretical
lines in conflict with possession.
If a land surveyor in making judgments is essentially trying to answer the question,
"where would a court find the line to be if presented with the same evidence?", the
differences in professional practice would seem perhaps to stem from the differing
emphasis that the case law of a particular state places upon the processes of
establishment by the "messy" methods of (a) practical location, (b) parole agreement
or (c) recognition and acquiescence.
My own impression from discussions with a colleague who practices in Montana is that  
in states that were originally well surveyed, both well measured and well monumented,
courts have tended to approach boundary matters in rather different ways from those
jurisdictions where the contrary was more often the case.
Kent McMillan, RPLS
Austin TX