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Legal implications of CAD-modified topo

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Message 1 of 15
C3D_RickGraham
342 Views, 14 Replies

Legal implications of CAD-modified topo

Hi all,



I'm doing some research into the legal implications on engineering firms modifying topo derived from the field.



I remember someone on here saying that their local (or state) says that ANY modification to survey is in violation but I cannot find that reference any more.



My real question, is how much do we skirt the edge of this? Is adding a breakline or swapping an edge in violation of this? For those who have this clause, is the wording subject to gross interpretation? I know that survey (especially GPS, or aerial, or point cloud) is the most accurate representation.



Any information that can be shared will be appreciated.



Rick
Thanks,
Rick
coauthor Mastering Civil 3D 2012
I blog at http://simplycivil3d.wordpress.com
14 REPLIES 14
Message 2 of 15
JFelshaw
in reply to: C3D_RickGraham

My thoughts on this is:

1. The triangles are software interpolative data between the real world data points.
2. The purpose of breaklines is to make a more accurate representation of the real world situation by adding restraints to the aforementioned software interpolated triangles.
3. While GPS is fairly accurate, it still only provides data for those points that were actually collected in the field and anything in between is still open for interpretation by either software or the software user.
4. As a general statement, aerial topography is great for large topographic areas, but to my understanding, does not carry the accuracy of a GPS or total station. In some cases the major contours are generated from the aerial photograph with minor contours interpreted.
5. Point clouds are to my knowledge the most accurate data that can be collected from the field to represent the real world environment. However, there is still the issues of post-processing the data. To create contours you still have the task of removing the noise and so on, I don’t know about you, but I don’t really care to see my contours running up every tree truck and power pole.

I know this was all an inflated response, but if someone has the idea that, “If the software generated it, then it is correct and it should not be touched”, then they are misinformed and/or have a lack of knowledge of how topography is generated.

I don’t really see the legal implications if someone adds user data to provide a more accurate depiction of the real world site, especially if that data could be confirmed with another visit to the field. On the other hand is someone was to manipulate the data collected from the field for whatever reason to deviated from the actually site, the I could very easily see how that could open them up for legal ramifications.
Message 3 of 15
Sinc
in reply to: C3D_RickGraham

I've never heard of it being a violation of law for an Engineer to modify the EG survey. But it isn't prudent for the most part.

If there is a problem, the best bet is for the Engineer to kick it back to the Surveyor, rather than "guess" and fix the problem, even though the Engineer may guess correctly much of the time. On the other hand, this isn't always practical. But if the Engineer decides to fix the problem without kicking it back to the Surveyor, the Engineer should do it with extreme care, and generally not unless a field visit verifies that the "fix" is more-correct than the original version from the Surveyor.

-- Sinc
http://www.ejsurveying.com
http://www.quuxsoft.com
Sinc
Message 4 of 15




I don't know the statute you refer to specifically. But most states have something similar. For the most part what they are referring to are the original field notes. In the age of Data Colletors that's why it's important NOT to edit the .RAW file. The original .RAW file should be preserved as evidence of what was done in the field.



As to TOPO. I learned to contour by hand about a quarter century ago. One of the most important things that the Surveyor who taught me this told me is "All contours are lies!". Whether done by hand or in a software program you have to field shots X distance apart. The draftsman or software assumes that there is a constant grade between those 2 points. That's never going to be the case unless you're shooting a sloped steel beam of something.



In the field the topo shots can verry too. On ground the tip of the rod can sink in soft soil. Even those crews that are careful about rod heights may be off a hundredth or two and I've seen crews who weren't very careful. And I've gotten rods directly from the factory that were incorrectly calibrated. So most contours represent a best guess.



But you asked about legally. As I said I believe the law are referring to the original field notes. But once you're in Court the Judge might interpret it anyway they feel fit. I once read about a case where a Judge decided in favor of one Surveyors work over anthers on the basis that the one Surveyor 'Followed in the original Surveyors footsteps". In that Judges eyes that meant that the guy who testified that they had cut along the boundary with machetes using transit and tape had fulfilled that requirement while the Surveyor who had used a random traverse using a total station had not. I think that "Following in the footsteps" more accurately means looking for and locating the evidence found and set by the original Surveyor. So once in Court you cannot rely on what interpretation may be put on a law. Makes it a lot of fun.

BTW. I'm currently waiting for the results of a case where my research took me back to Colonial Law and to Surveys done in the early part of the last century. I think we have everything nailed down. but you never know!

Allen



Allen Jessup
Engineering Specialist / CAD Manager

Message 5 of 15
davevoith
in reply to: C3D_RickGraham

Well we are a civil engineering firm in Illinois and we can even collect topo. We just don't do plat of surveys,stake lot corners, building corners, ect.
Message 6 of 15
Anonymous
in reply to: C3D_RickGraham


"All contours are lies!".

 

Thats precious. And I just tacked it up on my
monitor along with adding it to my signature <G>


--
Thanks, Joe

 

Joseph D. Bouza, P.E.
Civil 3D 2008
LDT 2008
Win XP pro
v 2002,
sp 2
hp workstation xw4600
Intel Core Duo CPU
E7200 @2.53 GHz
3 GB
RAM
NIVDIA Quadro FX 1700 (512MB)

"All contours are lies!" (courtesy of AJ )

The mantra of a former Flamer:

 

If you are forced to eat an Elephant, don’t complain about it; Take one
bite at a time.

 

*****************************************************************************************
In
memory of the King of Work-arounds
"The only Constant is Change".

 

"The only thing worse than training your staff, and having them leave is
-
not training your staff, and having them stay." 😮
A reminder taken
from Graphics Solution Providers' Calendar
page
*****************************************************************************************


style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">




I don't know the statute you refer to specifically. But most states
have something similar. For the most part what they are referring to are the
original field notes. In the age of Data Colletors that's why it's important
NOT to edit the .RAW file. The original .RAW file should be preserved as
evidence of what was done in the field.




As to TOPO. I learned to contour by hand about a quarter century ago.
One of the most important things that the Surveyor who taught me this told me
is "All contours are lies!". Whether done by hand or in a software program you
have to field shots X distance apart. The draftsman or software assumes that
there is a constant grade between those 2 points. That's never going to be the
case unless you're shooting a sloped steel beam of something.




In the field the topo shots can verry too. On ground the tip of the rod
can sink in soft soil. Even those crews that are careful about rod heights may
be off a hundredth or two and I've seen crews who weren't very careful. And
I've gotten rods directly from the factory that were incorrectly calibrated.
So most contours represent a best guess.




But you asked about legally. As I said I believe the law are referring
to the original field notes. But once you're in Court the Judge might
interpret it anyway they feel fit. I once read about a case where a Judge
decided in favor of one Surveyors work over anthers on the basis that the one
Surveyor 'Followed in the original Surveyors footsteps". In that Judges eyes
that meant that the guy who testified that they had cut along the boundary
with machetes using transit and tape had fulfilled that requirement while the
Surveyor who had used a random traverse using a total station had not. I think
that "Following in the footsteps" more accurately means looking for and
locating the evidence found and set by the original Surveyor. So once in Court
you cannot rely on what interpretation may be put on a law. Makes it a lot of
fun.

BTW. I'm currently waiting for the results of a case where my
research took me back to Colonial Law and to Surveys done in the early part of
the last century. I think we have everything nailed down. but you never
know!

Allen

Message 7 of 15

It helps put things in perspective. When I got good enough at interpolating by hand I would only actually calculate the 10' contours and just "sketch in" the ones in between. If there was a shot that showed a little bump I'd joggle the contour line one way or the other. I'd only interpolate the 2's in rugged areas. We never had anyone call us wrong or complain about the accuracy,

Of course physical objects are different. We were very careful to get as accurate an elevation as possible on Sanitary & Drainage features and at the Meet & Match for pavement.

Thanks for the attribution.

Allen


Allen Jessup
Engineering Specialist / CAD Manager

Message 8 of 15

Thanks all for you rcontributions (so far - I'm awaiting for the other side of the world to wake so I can hear some widom from a certain guy! 🙂



My real problem is that I think our survey department takes too many 'liberties' with contours. All because the field crew didn't get enough shots so CAD just tries its best to interpolate these and more times than naught is wrong. So then we have the survey tech (who hasn't been out in the field and perhaps looks at pictures, and then again perhaps not) make those decisions.



I was trying to think of a way to impress upon the Survey department head the importance of getting more shots - especially if they are using GPS. It is my humble opinion that too many shots is way better than not enough shots. We can weed out the ones we want to include via the point groups. With too little shots, then we get the weird contours which obviously don't look like that out in the field.



Rick



PS - I also love that saying and I'm posting it on my board too! 🙂
Thanks,
Rick
coauthor Mastering Civil 3D 2012
I blog at http://simplycivil3d.wordpress.com
Message 9 of 15

It it's "your" crews and you personally can't make that impression you need to keep asking for them to return to the field to get additional data. At some point the person in charge of the money will notice that they're billing a lot of time going back to jobs they should have been done with.

Have you tried explaining this to the head on your Survey Dept. like you've explained to us? I would hope they would listen to constructive criticism.

Along with enough shots they need to be collecting enough breaklines and collecting them correctly. One of our Departments got a topo survey from a consultant. It was done in LDT and had all the project files. The person asked me to take a look at it because it didn't look right. The contours showed very deep trenches running from the edge of a stream in to an adjacent property. I talked to the person I was helping and confirmed that there weren't any in the field.

The consultant had created the DTM and contours without the use of breaklines. I added them along the bottom & top of bank and along obvious physical features. That gave them a decent surface to work with. I never changed any of the original shots we were given. I just "tuned" the way the software was creating the surface. As far as flipping faces goes there is no way for anyone taking shots in the field to controll the direction the software will interpolate shots.

When I'm working my second job I'm often the one taking the shots in the field and doing the office work. So that makes it a lot easier. The place I mentioned getting my training at for a time had 2 party chiefs for one crew. One party chief would take the crew in the field while the other on stayed in the office and recuced tha last job he was out on. It made the reduction much quicker.

Allen


Allen Jessup
Engineering Specialist / CAD Manager

Message 10 of 15
Anonymous
in reply to: C3D_RickGraham


I don't understand why the state would dictate what
can be done with topo data. If an engineer modifies the topo from
a surveyor it would be an issue between the 2 in a lawsuit. The only case
where I would think the state would care is if the topo data were used in some
official way by the public or government and there are stringent standards for
that.

 

Am I missing something?
Message 11 of 15
Anonymous
in reply to: C3D_RickGraham

Hi Rick,

I guess you're referring to me as I've often posted on this subject in
the past.

I looked up widom and copied the initial results below"

#
ennifer Widom's Home Page
Stanford University - Databases: semistructured data and XML, data
warehousing and heterogeneous database integration, active database
systems, ...
infolab.stanford.edu/~widom/ - 16k - Cached - Similar pages
#
Jennifer Widom's Publications
J.D. Ullman and J. Widom. A First Course in Database Systems. Prentice
Hall, Upper Saddle River, New Jersey, first edition 1997, second edition
2002, ...
infolab.stanford.edu/~widom/pubs.html - 67k - Cached - Similar pages
#
The Widom Lab, BMBCB, Northwestern University
13 Jul 2006 ... widom lab. Home · lab members · about us · publications
· photo album · more info · contact. blank Home · lab members · about is ...
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Benjamin Widom is the Goldwin Smith Professor of Chemistry at Cornell
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FAQ ..... 18, Jennifer Widom: Deductive and Active Databases: Two
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A brief description of the research of Michael Widom.
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Kolomeisky, A.B. and Widom, B. A Simplified 'Ratchet' Model of Molecular
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Book results for widom
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356 pages
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A Dienstbier, ... - 304 pages


None of it seems particularly relevant to the OP's query 🙂

Let me say I'm amazed at the blind reliance on Lidar data as being the
"most accurate" by a couple of the posters here.

It is impossible to build a reasonable model of real world surfaces
without breaklines which Lidar data cannot document.

Even in the irrigation surveys of very flat natural landforms (typically
done here on a 25m to 50m grid), there are always a few items which
require breaklines for accurate representation.

To address the original question, I don't have knowledge of specific
legislation, but certainly the laws of consumer protection would apply
here. Adjustments to surface models made in the office on the grounds
of "contour appearance" in the absence of field information to support
it would not be defendable.


Regards,


Laurie Comerford



C3D_RickGraham wrote:
> Thanks all for you rcontributions (so far - I'm awaiting for the other
> side of the world to wake so I can hear some widom from a certain guy! 🙂
>
>
>
> My real problem is that I think our survey department takes too many
> 'liberties' with contours. All because the field crew didn't get enough
> shots so CAD just tries its best to interpolate these and more times
> than naught is wrong. So then we have the survey tech (who hasn't been
> out in the field and perhaps looks at pictures, and then again perhaps
> not) make those decisions.
>
>
>
> I was trying to think of a way to impress upon the Survey department
> head the importance of getting more shots - especially if they are using
> GPS. It is my humble opinion that too many shots is way better than not
> enough shots. We can weed out the ones we want to include via the point
> groups. With too little shots, then we get the weird contours which
> obviously don't look like that out in the field.
>
>
>
> Rick
>
>
>
> PS - I also love that saying and I'm posting it on my board too! 🙂
Message 12 of 15

From NYS Education Law: (My Bolding)

§7201. Definition of practice of engineering.


The practice of the profession of engineering is defined as performing professional service such as consultation, investigation, evaluation, planning, design or supervision of construction or operation in connection with any utilities, structures, buildings, machines, equipment, processes, works, or projects wherein the safeguarding of life, health and property is concerned, when such service or work requires the application of engineering principles and data.

§7203. Definition of practice of land surveying.



The practice of the profession of land surveying is defined as practicing that branch of the engineering profession and applied mathematics which includes the measuring and plotting of the dimensions and areas of any portion of the earth, including all naturally placed and man- or machine-made structures and objects thereon, the lengths and directions of boundary lines, the contour of the surface and the application of rules and regulations in accordance with local requirements incidental to subdivisions for the correct determination, description, conveying and recording thereof or for the establishment or reestablishment thereof.

§7208. Exempt persons.



This article shall not be construed to affect or prevent the following, provided that no title, sign, card or device shall be used in such manner as to tend to convey the impression that the person rendering such service is a professional engineer or a land surveyor licensed in this state or is practicing engineering or land surveying

e. Making of surveys by professional engineers, except that the determination of real property boundaries may be done only by a licensed land surveyor;



So the answer is: You can't do any Surveying (which includes plotting) unless you're a licensed Surveyor but Engineers can do surveys but can't determine boundaries.

Allen



Allen Jessup
Engineering Specialist / CAD Manager

Message 13 of 15
Anonymous
in reply to: C3D_RickGraham


I see. So I guess it comes down to whether the
professional licenses allow for it. I suppose it would come down to whether the
edits are done under the blessings of the licensee and whether that licensee
wants to take it to court.


style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
From
NYS Education Law: (My Bolding)

§7201. Definition of
practice of engineering.


The practice of the profession of engineering is defined as performing
professional service such as consultation, investigation, evaluation,
planning, design or supervision of construction or operation in connection
with any utilities, structures, buildings, machines, equipment, processes,
works, or projects wherein the safeguarding of life, health and property is
concerned, when such service or work requires the application of engineering
principles and data.

§7203. Definition of practice of land surveying.




The practice of the profession of land surveying is defined as
practicing that branch of the engineering profession and applied mathematics
which includes the measuring and plotting of the dimensions and areas
of any portion of the earth
, including all naturally placed and man-
or machine-made structures and objects thereon, the lengths and directions of
boundary lines, the contour of the surface and the application of rules and
regulations in accordance with local requirements incidental to subdivisions
for the correct determination, description, conveying and recording thereof or
for the establishment or reestablishment thereof.

§7208. Exempt
persons.




This article shall not be construed to affect or prevent the following,
provided that no title, sign, card or device shall be used in such manner as
to tend to convey the impression that the person rendering such service is a
professional engineer or a land surveyor licensed in this state or is
practicing engineering or land surveying

e. Making of surveys by
professional engineers, except that the determination of real property
boundaries may be done only by a licensed land surveyor;



So
the answer is: You can't do any Surveying (which includes plotting) unless
you're a licensed Surveyor but Engineers can do surveys but can't determine
boundaries.

Allen

Message 14 of 15

If the field work, reduction, plotting, tinning and tin edits were all done within the same company I can't see there being any problems. The sticky part comes in when a DTM done in a Surveyors office is edited by an Engineer, or someone working under the direction of that Engineer, in another office. At that point who becomes liable for any error (or perceived error)?

Allen


Allen Jessup
Engineering Specialist / CAD Manager

Message 15 of 15
Anonymous
in reply to: C3D_RickGraham


It seems clear to me that if an engineer makes
edits to the surveyors data he is taking on the liability for the TOPO and vice
versa.

 



style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">If
the field work, reduction, plotting, tinning and tin edits were all done
within the same company I can't see there being any problems. The sticky part
comes in when a DTM done in a Surveyors office is edited by an Engineer, or
someone working under the direction of that Engineer, in another office. At
that point who becomes liable for any error (or perceived
error)?

Allen

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