Importing Points - Assumed Datum

[Iceberg71]

What is the purpose/or value of shooting survey points in an assumed datum, importing them into Civil3D in an assumed datum, and then moving and rotating the points to the correct coordinates, such as NAD83?

I have been getting some concerns about this and need to get some information so that they can be addressed appropriately.

Thank you for your input on this matter.

[L3GO-Ed]

If one had the Datum data on or near site, It wouldn't any that much value. However often, like in our country, you may be compelled to carry out asurvey before you get hold of the datum data, that way you use assumed coordinates, import them before recieving the data, and later get the data and rotate to the correct coordinates. It may sound hypothetical from where you are standing but from my end, happens alot.

[KirkNoonan]

You might also have an older survey or points that were originally observed in an older datum, or points from another surveyor that doesn't adhere to the same quality standards that you do. If you can go back after the fact and locate two or three of the originally used control points, then you can translate the survey database which would put everything in the right place.

[Iceberg71]

This is what they are doing for all of the new projects that they are getting field work done for.

The issue is, that when the points are imported into Civil3D, Civil3D is generating a rough Tin and drawing in linework.  All of this stuff needs to be moved as well when moving the points.  Sure if you forget to move the surface or linework you can recreate the objects realitively easily but it kind of depletes the purpose of having Civil3D generate this stuff.

If this is a typical procudure among the industry to move the points after being imported then I will update my template file to not create the Tin and linework.  The easy solution to me is just to shoot the points in the right coordinate system.  So thats what I am trying to figure out, what is the best approproach.

[KirkNoonan]

Any auto-generated linework (survey figures) or surfaces will follow the points when the database is translated. That is the advantage of it.