AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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*Expert Elite*
antoniovinci
Posts: 1,740
Registered: ‎06-03-2011
Message 11 of 18 (688 Views)

Re: PNT files

03-16-2012 11:43 AM in reply to: Jeff_M

Jeff_M wrote:
does he shoot contours, or does he shoot points with elevation?
He shoots points with elevation, then he comes back home, and the very first thing he makes is.. contours from those points.
Contours are the base for every serious topographic plan: how did you project before computer era?
Answer: in 2D, on a contour basis, trust me.
If somebody lets me choose between a bunch of 3Dfaces (TIN) or a shape with elevated contours, I go with the second one, without no doubt, dear Jeff.
Distinguished Mentor
andrewpuller3811
Posts: 785
Registered: ‎07-30-2008
Message 12 of 18 (672 Views)

Re: PNT files

03-18-2012 03:11 AM in reply to: antoniovinci

antoniovinci wrote:

Jeff_M wrote:
does he shoot contours, or does he shoot points with elevation?
He shoots points with elevation, then he comes back home, and the very first thing he makes is.. contours from those points.
Contours are the base for every serious topographic plan: how did you project before computer era?
Answer: in 2D, on a contour basis, trust me.
If somebody lets me choose between a bunch of 3Dfaces (TIN) or a shape with elevated contours, I go with the second one, without no doubt, dear Jeff.


The first thing that gets done with points are that they are added to a surface in civil 3d from which trianlges are created, from which contours are interpreted. Check out what gets changed when contours are smoothed.

 

When I carry out a topo survey I measure points (and breaklines) that will create a surface model that will give the best representation in the computer of the actual ground, based on triangles.

 

Before computers, surfaces were drawn with contours, which were calculated from the points that surveyors measured. The surveyed points were plotted onto paper then measured between to calulate the elevations that were to be drawn as contours. The contour lines would then be drawn smoothly between all the calculated elevations of the same height to give your contour plan. The same process that occurs with a tin surface in computers.

 

If this fixed your issue, click on "Accept as Solution"

Andrew Puller
Maitland, NSW, Australia
Windows 7 Enterprise 64bit
Intel core i7 2600 @ 3.40 GHz with 16GB Ram
Civil 3d 2013 64bit
*Expert Elite*
BrianHailey
Posts: 2,849
Registered: ‎04-27-2005
Message 13 of 18 (664 Views)

Re: PNT files

03-18-2012 10:55 AM in reply to: antoniovinci

Contours are a lie. I would MUCH rather have the triangles of the surface then an approximation of the surface aka contours. If you build a surface from contours, what is happening between the contours? You have absolutely no idea. If you get the triangles, you have the maximum amount of information from that surface. Do you build from contours? No. You build from points. The contours are simply a graphical representation of those points that make it simple for us as humans to see what is going on.

 

I hate to say it but I disagree with you, Antonio (I'm assuming that's your first name). But hey, that's the great part about this discussion group, people disagreeing with you is a great way to learn.

Brian Hailey
CAD-1.com
My Blog
*Expert Elite*
wfberry
Posts: 1,914
Registered: ‎09-05-2006
Message 14 of 18 (640 Views)

Re: PNT files

03-19-2012 09:27 AM in reply to: BrianHailey

Brian:

 

The biggest problem that I have here is agreeing with Jeff, ALL THE TIME.  

 

Oh well, maybe, someday!

 

:mansad:

 

Bill

Contributor
aportillojr
Posts: 14
Registered: ‎03-29-2011
Message 15 of 18 (633 Views)

Re: PNT files

03-19-2012 03:11 PM in reply to: Jeff_M

I am going to consider this issue resolved for me.  In future I will ask for LandXLM file.  I was actually looking for points.  When I received the .txt file with point information, I imported .txt file and got what I was looking for.  I appreciate all the good answers.  When I called the surveyor, he didn't know anything about a .pnt file. I use him regularly therefore I will just get the .txt file and insert it.

 

Thanks again,

Mando

Valued Contributor
jmatte2004
Posts: 69
Registered: ‎02-01-2012
Message 16 of 18 (618 Views)

Re: PNT files

03-20-2012 09:56 AM in reply to: aportillojr

tell your surveyor to throw away that toy for software he has and get some real software. i always have problem with surveyor that have carlson. i bata tested it when it first came out and even meet with the developer to get him to fix the problems. seems like they still have some of the same problems today.

Distinguished Contributor
Hammer.john.j
Posts: 130
Registered: ‎05-06-2008
Message 17 of 18 (369 Views)

Re: PNT files

08-23-2013 06:37 AM in reply to: antoniovinci

contours CAN be basis for work if the contours are from an Aerial Survey using photogrammitry and mathematical cmoputations to out put contours...

 

Different types of survey are source data are applicable to different project types and accuracies with most detailed contouring requiring field survey which uses the compilation of points to create a grid surface or triangulated irregular network (surface).  Surfaces can also be made from aerial survey points acquired from LiDAR for instance.

 

http://en.wikipedia.org/wiki/Triangulated_irregular_network

John Hammer, LA
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Distinguished Contributor
Hammer.john.j
Posts: 130
Registered: ‎05-06-2008
Message 18 of 18 (367 Views)

Re: PNT files

08-23-2013 06:43 AM in reply to: jmatte2004

Carlson is actually a very good program for Survey, it works very well with data collectors (Trimble I think?).  Civil 3D is a good upgrade but not being a surveyor, I can't say if Civil 3D handles field to finish as well as Carlson or how well it works with Data Collectors.  Carlson actually works quite well with Civil 3D and to the O.P.... consider asking for:

 

XML of surface

text file of points

2D Cad linework

 

YOU DON'T need their triangles, their cad blocks (survey shots) but you PROBABLY want their contours to get their representation of the contours to make sure Civil 3D's interpretation of the XML file matches.... 

John Hammer, LA
Dell Precision T3500 - Xenon W3550 @ 3.07 (4 core)
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Cat 6 network with GlobalScape Avail Agent - WAFS
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