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Grid to Ground Coordinates

27 REPLIES 27
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Message 1 of 28
jgemperline
4565 Views, 27 Replies

Grid to Ground Coordinates

Hey All,

I have been asked to convert my design in Civil 3D from Grid (Wyoming East Zone, U.S. Survey Feet) into Ground Coordinates (combined Scale Factor =0.99971591, Grid to Ground = 1.000284171). Can this be done in the Transformation Tab?

Thanks
Joe
27 REPLIES 27
Message 2 of 28
Anonymous
in reply to: jgemperline

You have two options here.

1. Wait for sinc to answer.
2. Search this NG for sinc's answer. I believe he answered this within the
last month or two.

Bill

wrote in message news:6390935@discussion.autodesk.com...
Hey All,

I have been asked to convert my design in Civil 3D from Grid (Wyoming East
Zone, U.S. Survey Feet) into Ground Coordinates (combined Scale Factor
=0.99971591, Grid to Ground = 1.000284171). Can this be done in the
Transformation Tab?

Thanks
Joe
Message 3 of 28
Anonymous
in reply to: jgemperline

And I hope RK stops in to read this too........

--

Murph
http://map3d.wordpress.com/


"wfb" wrote in message
news:6390966@discussion.autodesk.com...
You have two options here.

1. Wait for sinc to answer.
2. Search this NG for sinc's answer. I believe he answered this within the
last month or two.

Bill

wrote in message news:6390935@discussion.autodesk.com...
Hey All,

I have been asked to convert my design in Civil 3D from Grid (Wyoming East
Zone, U.S. Survey Feet) into Ground Coordinates (combined Scale Factor
=0.99971591, Grid to Ground = 1.000284171). Can this be done in the
Transformation Tab?

Thanks
Joe
Message 4 of 28
mvilla724
in reply to: jgemperline

joe, i haven't used c3d transformation tab to scale survey data yet, you can certainly use the scale command and use your base, ngs point, 0,0, etc. as the base point (old school). when i have time i'm going to try it. that's the coordinate system i live and work in, cool. good luck.

Michael
Message 5 of 28
jgemperline
in reply to: jgemperline

My hope is that I can scale/transform my model and all my lables and tables update. I have a road alignment, profile and coridor that will be effected too.

Thanks
Joe
Message 6 of 28
mvilla724
in reply to: jgemperline

right, i'd do a save as and give a shot. from what i've heard of the map 3d functions, transformations are a selling point for these guys. let me know if this works.
Message 7 of 28
stacy.dunn
in reply to: jgemperline

It sounds like you are done with your design and transforming that many interconnected objects will probably not end well. Why do you need the project in a surface system? Could you simply provide the construction surveyor or contractor a scale factor and have them work in grid?
Stacy Dunn
Message 8 of 28
Sinc
in reply to: jgemperline

The Transformation Tab will not change stuff that's already in your drawing. If they had given you this request BEFORE you did your design, then it would have been relatively easy to setup the Transformation Tab for it, and then do your design on ground.

One of the most important guidelines of design is to decide on your coordinate system BEFORE starting ANY work on a project, and then keep that coordinate system throughout, from beginning to end. As it is, you have a problem.

You can try scaling everything using the Autocad SCALE command, and depending on what all is in your DWG file, it might actually work. Let us know...

(Of course, the BEST solution is to keep it in State Plane the way you have it, but I know what sort of battle that can be...)

-- Sinc
http://www.ejsurveying.com
http://www.quuxsoft.com
Sinc
Message 9 of 28
jgemperline
in reply to: jgemperline

lol, Stacy that is exactly what I was thinking when they asked me to do this. That is what we have been doing forever. This project had a reviewer from the construction office that made a comment and stood his ground, untill our office gave in to his wants.

Thanks
Joe
Message 10 of 28
stacy.dunn
in reply to: jgemperline

How large/long is the site?
Stacy Dunn
Message 11 of 28
Sinc
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
Message 12 of 28
jgemperline
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.
Message 13 of 28
jgemperline
in reply to: jgemperline

I did not have a say in it. I just got the orders.
Message 14 of 28
jgemperline
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
Message 15 of 28
Anonymous
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.
Message 16 of 28
mvilla724
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
Message 17 of 28
Sinc
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
Message 18 of 28
jgemperline
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
Message 19 of 28
Sinc
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
Message 20 of 28
Anonymous
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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