Subject: UK Construction Industry Websites
From: cebab@cix.compulink.co.uk ("Andrew Hudson")
Date: Sat, 16 Nov 1996 00:01:55 GMT
Please visit the WWW site of C E Ball & Partners, Chartered Quantity
Surveyors, Construction Cost Managers and Project Managers. Active
throughout the UK on major projects and with a keen interest in the cost
management of M&E; and vertical transportation installation as well as
general construction works, high quality fitting out and retail
shopfitting.
http://www.ceb.co.uk/
The site include lots of construction and design related www links.
C E Ball are also founder members and active participants of CITE and 2
years ago were the first QS in the UK to produce CITE compliant
Electronic Bills of Quantity (EBQ's).
Please also then visit .....
CITE (Construction Industry Trading Electronically) the Home
page for this UK initiative to provide a pragmatic approach to
the electronic transfer of Tender information in the form of
Bills of Quantity (EBQ's) between the Client QS and the
Contractor's Estimator - and back. Download a trial 'zip'
file to see what its all about. Visit CITE at:
http://www.cite.org.uk/
Here you can find out about the various CITE Initiatives, find
out how to join, lookup members activity and links to their
own websites, and download the CITE BOQ FREEWARE!
Please visit soon!
_____________________________________________________________________
Andrew Hudson BSc FRICS, C E Ball & Partners, London
cebab@cix.compulink.co.uk
_____________________________________________________________________
Subject: Re: GPS vs Traditional Surveys
From: saramc@cc.utexas.edu (Kent McMillan)
Date: 16 Nov 1996 01:18:07 GMT
>This can be a very good thread, I think. These are issues we need to
>deal with and the internet is the ideal forum in many ways. I hope
>you don't mind my posting this reply in the news group.
>
It seems to me that there are four verbs that pretty much encompass the work of land
surveyors:
- Dig,
- Measure,
- Judge, and
- Preserve.
Only one of these describes a part of surveying that is much affected by GPS
technology, all of the marketing hooplah to the contrary not withstanding.
D i g g i n g :
Surveyors dig up (both figuratively as well as literally) the evidence that pertains
to the question of the location of specific land boundaries. In my view, deed
research at the County Clerk's office is digging and so are preparing working
sketches and making up "shopping lists" of things to be examined further upon the
ground.
Obviously digging is an essential part of a land survey, otherwise one could measure
forever without ever discovering anything about the property rights that are the real
object of the land survey investigation.
Digging is a professional skill that cannot be easily taught because the inquiry
depends upon what is found and requires a varied knowledge of the habits and customs
of the previous surveyors one is following. The best actual corner monument finders
I know are both older colleagues who have spent a good bit of professional time in
field. The worst records for corner recovery probably belong to firms who have
decided that the investigative part of surveys can be done by inexperienced staff
directed by remote control from the office.
M e a s u r i n g :
It is the measuring aspect of land surveying that is the activity that is fixed in
the mind of the public (and of the people who sell survey equipment) as being what
land surveying is all about. When the newspaper comes to interview you, would you
rather be photographed standing next to a surveying instrument or carrying a shovel,
or slaving at a desk over a pile of deeds? I'm afraid that I would head for the
instrument if I wanted a picture that non-surveyors would recognize.
Measuring as a professional skill lies in knowing how to efficiently perform
reliable measurements, matching suitable equipment and methods to a particular task.
It also lies in knowing what sorts of things can go wrong, so that the work is
carried out with an eye open for blunders and an awareness of the effect of the
inevitable small errors. As measuring equipment gets more sophisticated, the
surveyor is roughly in the same relation to it as the well qualified airline pilot
is to the automated flight control systems. I don't know about you, but the first
time I hear a synthesized voice say "this is your pilot ...", I'll be wishing that I
had my parachute with me. Technology is great until it doesn't work.
I would think that roughly one-fourth of the work of a typical land survey is the
actual measuring. I consider the fundamental calculations to be an extension of the
measuring process. Inverse calculations from surveyed co-ordinates are a sort of
second or third generation measurement, and some knowledge of the uncertainties in
the co-ordinate values is just as important as, say centering the instrument or
plumbing the prism rod was in the field.
GPS technology will only effect this small part of land surveying in Texas, the
measuring, for the forseeable future.
J u d g i n g :
The digging and measuring present the surveyor with evidence to be weighed and
considered. This judging of the evidence is where the experience and skill of a
professional indispensible. Judgment comes from being in the arena, trying to
apply general principals to specific situations that have a remarkable way of
resisting generalization. What makes surveying a fit profession for an adult is that
one can work at it for a lifetime and still find novel situations that defy any
"cookbook" procedure.
Unfortunately for the popular conception of surveying, it is a perfectly sedentary
activity that does not lend itself to being photographed in the Swiss alps, or at a
construction site wearing designer clothing. I think that we would hear more about
the judging aspect of land surveying if the professional magazines were to solicit
advertising from the makers of Maalox.
P r e s e r v i n g :
When all is said and done, the actual tangible products of a land survey are maps,
reports, written descriptions, and possibly some new boundary markers. Since they
are the actual thing that the client receives, they are from a professional practice
standpoint the most important part of a land survey.
The ability to explain in clear language to a client what one has done and found is
a professional skill that cannot be automated. The art of writing descriptions that
can be located, and properly understood, by some land surveyor fifty years from now,
is not easily mastered.
Of the above, only measuring is the part that has really changed much over the last
forty years in Texas, where I practice. It would be interesting to know whether
measuring figures more significantly in the land surveying process for surveyors
practicing inside a Torrens system of title registry (such as the Australians and New
Zealanders have), and digging less so. How does the above mix of activities play out
in their respective practices?
Kent McMillan, RPLS
Austin TX
Subject: Re: 'Double-ing(?) angles with a total station
From: Peter Ehlert
Date: Sat, 16 Nov 1996 08:33:53 -0800
Neil Giesbrecht wrote:
>
> With modern instruments is turning the angles twice on opposite sides of
> the 'plate' necessary? In my case I own a Leica TC600 and turning angles
> (actually bearings) twice on opposite faces is basically a pain in the ass
> since the display is only on one side of the gun and it doesn't 'hold' the
> foresight to use as the subsequent backsight. Does the circuitry of these
> new guns make such a routine unnecessary?
>
> It has me wondering
"Modern instruments make VERY accurate measurements.
We no longer have a need for doubling."
--> I made that statement when I got my first Wild T1 in about 1973.
I was right then and am still right.
Doubling does NOT increase the _accuracy_ enough to warrant the effort.
The REAL reason to double is (and always has been) to eliminate People
Errors.
1. We ALL make transcription errors. It is Very common to swap numbers,
write unclearly, record the vertical instead of the horizontal, . . . .
The list is endless. "I am very careful and don't do that": BS, we are
human. "I use a data collector": not out of the woods yet!
2. We ALL make pointing errors. In the best of conditions we get
complacent and make silly, sloppy errors; in tough conditions we can be
mistaken. Pointing to the wrong sight can and does happen, pointing a
little off the target happens too.
A bad double tells you that you have an error someplace. This is
probably the only way the error can be found. Balancing a traverse does
no more than spread the error thru your Good work.
**>>> Don't Skip Doubling, you will screw up, guaranteed. <<<**
We are getting lost in technology and forgetting real life conditions.
----- (you may replace "doubling" for "redundant independent
measurement" at any point in this discussion) -----
--
Peter Ehlert mailto:petere@sonic.net
Oooo.
.oooO ( )
( ) ) /
\ ( (_/
\_)
Sea Dance Internacional, SRLdeCV
Subject: Re: 'Double-ing(?) angles with a total station
From: Chris Hall
Date: Sat, 16 Nov 1996 11:55:54 -0500
Paul Kunkel wrote:
> I once test-ran a very inexpensive Leica total station at a
> convention. That may have been the TC600. It appeared to be built for
> staking and topo, the kind of work that requires little high-order
> traversing. One-sided angles may be safer now that such things as
> dual-axis compensation and stored error constants are available, but does
> that instrument even have those features?
As a side note, we were only able to accomplish a 1:27000 accuracy on a
13 angle, 2100m traverse. Then again, we are only students, however we
took 4 or 5 sets at each station and were out by 24" on the whole
traverse.
I don't know if that's good or bad for a total station that really isn't
made for traversing.
--
Humans are merely a life support system for their cats.
=======================================================
Chris J. Hall jkh@synapse.net Ottawa ON
Canada
=======================================================
Subject: Re: 'Double-ing(?) angles with a total station
From: dine@powerup.com.au (Peter & Carmel Spierings)
Date: 16 Nov 1996 20:09:08 GMT
In article <01bbd10a$d11f7b00$7046aecc@neilkg.netshop.net>, Neilkg@netshop.net says...
>
>With modern instruments is turning the angles twice on opposite sides of
>the 'plate' necessary? In my case I own a Leica TC600 and turning angles
>(actually bearings) twice on opposite faces is basically a pain in the ass
>since the display is only on one side of the gun and it doesn't 'hold' the
>foresight to use as the subsequent backsight. Does the circuitry of these
>new guns make such a routine unnecessary?
>
>It has me wondering
From my experience in deformation and general control surveys, the use of
a Total Station does not relieve the Surveyor from the responsibility of
applying basic principles and precautions in carrying out any type of
survey. Many surveyors regard the Total Station as a magic wand and they
conveniently overlook the fact that at each set-up the theodolite has to
be fully calibrated anew. Only when this is done can we speak of
advantages of the Total Station.
The use of Least Squares in adjusting traverses is quite meaningless as
the redundancies in a traverse are very small in number. The use of
Least Squares assumes that, apart from small random errors in the
measurements, the number of redundancies is significantly large.
Nonetheless, many surveyors keep on using least squares to adjust
traverses. Bowditch would be much more preferable.
Subject: Re: Job prospects for a Survey Technician
From: "Alan B. Chace"
Date: Sat, 16 Nov 1996 16:06:26 -0800
In upstate New York, there is practically no demand at all
for surveying technicians. Those few who find jobs can expect
to earn $6-$9 an hour. The work is seasonal and unsteady. Job
security, benefits, vacations, and such are unheard of.
My class graduated 7 Surveying Technicians in 1992. I am the only
one still surveying, another is doing construction inspection. Both of
us were older students. None of the graduates in their 20's without
prior surveying experience ever got any survey work. One of them
carries the U.S. mail, he makes a lot more than me.
Alan B. Chace, PLS
Bainbridge, New York
Subject: Re: 'Double-ing(?) angles with a total station
From: n9649893@scooter.cc.wwu.edu (Paul Kunkel)
Date: 16 Nov 96 23:47:21 GMT
Chris Hall writes:
>As a side note, we were only able to accomplish a 1:27000 accuracy on a
>13 angle, 2100m traverse. Then again, we are only students, however we
>took 4 or 5 sets at each station and were out by 24" on the whole
>traverse.
>I don't know if that's good or bad for a total station that really isn't
>made for traversing.
Let me suggest that it may be misleading. One major source of
theodolite error is eccentricity of the trunnion axis, the axis about
which the scope plunges. If the trunnion axis is not horizontal, then as
the scope is tilted, the line of sight will cut a plane which is not
vertical. This will lead to angular error, but it is quite possible to
get a deceitfully good closure in spite of it.
Suppose that the trunnion axis is skewed clockwise from the gunner's
perspective. Now suppose that a traverse is being run down a steep hill,
and that the instrument is not being inverted. All of the angles will
appear larger than they actually are, say 15" larger. If it takes six
stations to get to the bottom, that comes to 1'30". After traversing
through a few more stations at the bottom, the party heads back up the
hill. This time the observed angles are 15" too small, because the
conditions have been reversed. If they use six stations going up the
hill, then the angular error will have been completely canceled. That
is not a good traverse though.
Those who read from both sides and use the same instrument every day
may notice this effect when they reduce notes. The error will tend to be
greater on the steep shots, and its sign will depend on whether the
traverse is running uphill or downhill.
Kunkel
