AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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*Expert Elite*
Sinc
Posts: 6,207
Registered: ‎11-18-2006
Message 11 of 28 (1,286 Views)

Re: Grid to Ground Coordinates

05-13-2010 01:11 PM in reply to: jgemperline
Good point... If the site is large enough (in any direction), you'd have a good argument that you CAN'T convert the project to a ground system without negatively impacting the integrity of the design...

-- Sinc
http://www.ejsurveying.com
http://www.quuxsoft.com
Sinc
Valued Contributor
jgemperline
Posts: 60
Registered: ‎01-09-2008
Message 12 of 28 (1,286 Views)

Re: Grid to Ground Coordinates

05-13-2010 01:12 PM in reply to: jgemperline
Not very large. There are two areas/roads near each other separated by about a mile. Each road is about 1 mile long. If that make sense.
Valued Contributor
jgemperline
Posts: 60
Registered: ‎01-09-2008
Message 13 of 28 (1,286 Views)

Re: Grid to Ground Coordinates

05-13-2010 01:20 PM in reply to: jgemperline
I did not have a say in it. I just got the orders.
Valued Contributor
jgemperline
Posts: 60
Registered: ‎01-09-2008
Message 14 of 28 (1,286 Views)

Re: Grid to Ground Coordinates

05-13-2010 01:28 PM in reply to: jgemperline
Michael,

I'm not a survey person at all. If I were to attempt the Manual Scale all method, would I need a special point to scale from (a common point)? I'm trying to visualize how this works and cant see this point. Can you explain?

Thanks
Joe
*neilw
Message 15 of 28 (1,286 Views)

Re: Grid to Ground Coordinates

05-13-2010 01:28 PM in reply to: jgemperline
I have often questioned the workflow that is based on designing on grid
coordinates. I do understand that a grid based project is better suited for
integrating georeferenced data from various sources, but it is not a good
choice for the design which should be done in true length ground distances.
It seems to me the workflow should be reversed, that is, to design on ground
and transform to and from grid when there is a need to integrate or export
data to other sources. Agencies that want the data in grid coordinates for
their mapping systems don't usually require the degree of accuracy as do the
engineers designing the project, so it would not be as critical to transform
data from ground to grid when they request it vs. the other way around for
contractors and designers.

I'm interested in hearing the arguments for designing on grid.
Active Contributor
mvilla724
Posts: 49
Registered: ‎11-07-2002
Message 16 of 28 (1,286 Views)

Re: Grid to Ground Coordinates

05-13-2010 01:38 PM in reply to: jgemperline
Joe, the source of the scale factor will be your starting point. if it was the surveyor (most likely) that gave you this factor, asking him from where the survey will be scaled from is your best bet. i've been in wyoming for a year and still marvel at how few ngs points we have compared to arizona. so depending on what the control situation is, it could be an average of 2 or more control points, etc., scaled from the base, 0,0, or even a temp. control point. but the surveyor or department/company he works under is the key. good luck. i'm not the say all, but have been drawing survey maps for few minutes now ;-) don't hesitate to ask.

Michael
*Expert Elite*
Sinc
Posts: 6,207
Registered: ‎11-18-2006
Message 17 of 28 (1,286 Views)

Re: Grid to Ground Coordinates

05-13-2010 01:45 PM in reply to: jgemperline
> {quote:title=Guest wrote:}{quote}
> I'm interested in hearing the arguments for designing on grid.

I would suggest that's a topic for another thread... It could rapidly overburden the OP's question if we discussed that topic in this thread.

-- Sinc
http://www.ejsurveying.com
http://www.quuxsoft.com
Sinc
Valued Contributor
jgemperline
Posts: 60
Registered: ‎01-09-2008
Message 18 of 28 (1,286 Views)

Re: Grid to Ground Coordinates

05-13-2010 01:50 PM in reply to: jgemperline
Thanks!!!

I will keep you posted on how this shakes out!!! We should have a meeting with the survey group soon.

Thanks Everyone!!!
Joe
*Expert Elite*
Sinc
Posts: 6,207
Registered: ‎11-18-2006
Message 19 of 28 (1,286 Views)

Re: Grid to Ground Coordinates

05-13-2010 01:50 PM in reply to: jgemperline
The standard method of scaling in this situation is to use (0,0) as the base point. I've seen people use other base points, but it carries a lot more potential for confusion and problems. It's usually better to keep it simple.

Really, someone needs to talk to the reviewer, and explain why his request is very likely not the best route to follow. But I've been in your position, and I know how those discussions can go. This topic is frequently misunderstood. It's sometimes possible to explain things, but it takes a lot of effort, and a very careful approach. It's all too easy for the other person to shut down on this topic, and fail to hear anything you say.

-- Sinc
http://www.ejsurveying.com
http://www.quuxsoft.com
Sinc
*neilw
Message 20 of 28 (1,286 Views)

Re: Grid to Ground Coordinates

05-13-2010 02:56 PM in reply to: jgemperline
Yes you are right. It's a peeve of mine and the topic got me going, but this
is not the place.
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