Point Transformation Reference point

[Anonymous]

I receive a point file from the surveyor and he uses 9999.9800, 9999.9800
for point number 1. I import the file and move all the points to their
respective positions in my drawing file set to California NAD 83 zone IV
foot giving point number 1 a new coordinate.

Now I receive another (the same) file from the surveyor with some missing
and added points. Point number 1 is still at 9999, 9999. I see in my drawing
settings the transformation tab there is a Reference Point option. Do I just
select point number 1 (with it's new "imported" lat/long) for the reference
pont, import the new file and check "do coordinate transformation if
possible"? Will all the new points import and find their correct positions
with the existing point file? I would try it but I'm waiting for the new
file. I'd like to make this work when it gets here instead of "moving" all
the points manually again.
Thanks

[Sinc]

> {quote:title=Guest wrote:}{quote}
> I see in my drawing
> settings the transformation tab there is a Reference Point option. Do I just
> select point number 1 (with it's new "imported" lat/long) for the reference
> pont, import the new file and check "do coordinate transformation if
> possible"?

No.

The "Do Coordinate Transformation if possible" option is when you specify one coordinate zone in your drawing, and another coordinate zone in your Point File Format, and you want to reproject the points between the two different projections.

If you are using the Transformation Tab, then each point will have both a (Northing,Easting) coordinate pair and a (GridNorthing,GridEasting) coordinate pair. You need a Point File Format that imports the correct values. So depending on your exact task and on how you configure the Transformation Tab, you may need to create a new Point File Format that uses the Grid Northing and Grid Easting, instead of the Northing and Easting.

I have an article on Civil 3D's Transformation Tab that might be useful. I also have a video demonstration on converting between Project and Grid Coordinates that might be helpful. That video illustrates a task almost identical to what you want to do. The only difference is that, since you are importing things from an assumed system into a State Plane grid, you may also need to specify a scale factor on the Transformation Tab, to get from ground to grid.

-- Sinc
http://www.ejsurveying.com
http://www.quuxsoft.com