Grid Easting-Northing, Different with NO Transformation

[envirocad]

I have a drawing with Benchmarks and noticed that the Easting-Northing was slightly different than the Grid Easting-Grid Northing. I was using a State Plane coordinate system, but did not have any Transformations applied. Finally i changed my Coordinate System to "No Datum, No Projection" applied the settings, then set the drawing back to the same State Plane Coordinate System and that magically fixed my problem. Now, the corrdinates readout the same for Easting-Northing & Grid Easting-Grid Northing. Is this some type of bug? or did i do something wrong? I would hate to give out incorrect coordinates somehow in the future.

Thanks,

Scottie

Civil 3D 2011, 64 bit

[ericcollins6932]

I'm guessing a part of your state plane coordinate system includes a grid scale factor. Plain old E,N are typically plane or ground distance. Grid distances are those ground distances reduced to sea level and then grid ; therefore the difference between grid and standard. Setting datum to none, you are making an assumption. People that receive your file will now have to know your coordinates are indeed state plane to use them properly.

[envirocad]

I have reset coordinate system back to State Plane. There is not a difference between E,N & Grid E,N anymore. Just noticed that there was a difference before resetting the corrdinate system. Seems odd to me.

[Morshcaborsh]

I am having the same problem.  I'm using Civil 3D, 2012, my coordinate system set in the drawing is UTM83-15F.  When I insert my points from my database into my drawing, not only are the coordinates different, but they're inserted in the wrong location, being inserted at the "Northing" & "Easting", instead of the "Grid Northing" and "Grid Easting".  I've checked my coordinate systems in both my drawing and my database.  They both match, and I do not have a transformation set in my drawing settings.

I tried your trick of turning the coordinate system off then on and that seems to fix it for now, but this is dangerous.  We were lucky on this project in that we had an xref of the same information that was correctly inserted that showed us that our points were in the wrong location.  If not for that catch, we would quite possibly not caught it.

Does anyone know of any other switch in Civil that could possibly be modifying my points?

Pre fix:

       Northing : 10930348.2807'
            Easting : 1503119.8822'
    Point Elevation : 2.846'
 Grid Northing : 10930326.4200'
       Grid Easting : 1503116.8760'
           Latitude : N30° 06' 52.77"
          Longitude : W93° 26' 03.85"
       Scale Factor : 1.000
        Convergence : -0° 13' 04.64"
  

Post Fix:

      
           Northing : 10930326.4200'
            Easting : 1503116.8760'
    Point Elevation : 2.846'
 Grid Northing : 10930326.4200'
       Grid Easting : 1503116.8760'
           Latitude : N30° 06' 52.77"
          Longitude : W93° 26' 03.85"
       Scale Factor : 1.000
        Convergence : -0° 13' 04.64"
    

[ericcollins6932]

Ensure your survey database is set properly as well. Scale factor of 1.0 suggests to me something is wrong.