Or maybe its top secret. Is it a radial scale factor broadcast from the identified central point? Or some other conversion? It would be nice to know so I dont have to spend time trying to figure it out.

Sorry, Im speaking of the Solutions software.
Modified By Norm Miller on 11/19/2001 at 6:11 PM

The solution as explained to me by Rex Williams (Ashtech dealer) is to create another customized user-defined export file format that will export coordinates that have been transformed in the software program.

Create a new user ascii template called LOCALGROUND (as an example). Select the following items from the available fields list:

[site ID][local/ground northing][local/ground easting][orthometric height]

When you now use the export project coordinates choose your new ground coordinate template and not the one you may have been using for grid coordinates. Give a name to your coordinate file and then select the save button. You should now get an ascii file that will match your transformed ground coordinate system. I find that it does work as Rex had explained. Thanks again Rex

I guess my original post must have been confusing. Im not asking how to export ground coordinates. What I wanted to know was how Solutions calculates to ground from grid. Other GPS software has you define a point on your project as a hold point and uses the combined scale factor for that particular point applied radially away from that point as it relates to grid inverses. This is ok to an extent but the further away you go from the hold point the worse the results get compared with EDM distances. Hope that makes sense. I can check this against other software conversions, but I thought someone on this board would know.

NM

Norm,

Solutions uses a centroid in the approximate center of your project.

The inaccuracies you mentioned are inherent to using a ground plane coordinate system.

Brian