I have made a circuit to opto isolate my DRO output so I can feed them into the DRO/MPG inputs, I have made a script to move the axis a curtain amount pause then write the real position from the 1 micron scales to a file and chart the accuracy of my system.
 What would really be the icing on the cake, would be to be able to use this data as input to the screw mapping feature but I don't
understand the file format that mach3 uses. Any help in this department would be greatly appreciated.

I may have not used the best wording to describe what I am trying to do, I have looked at all the posts on this subject so
I know the basic layout of the data but I don't know how to turn a CSV into the garbledegoop I see when I look at the curve.dat
with notepad

You could try manually inputting some correction values through the config\screwmapping menu and inspecting the file so generated?  I would guess that the format should be obvious from that.  Actually generating the file from your CSV might involve some creative Excel work; or you could open the csv in a text editor and use that to insert necessary formatting characters.  This sounds harder than it usually turns out to be as you can use the "replace all" command creatively.

Hi John, thanks for the reply, that is what I did but I am not a programmer so what I saw made no sense to me.
I did not recognize any of the characters and there were no numbers but I was using notepad to view it. It is nice to
have the ability to feed the values from the scales back into mach3, I made multiple runs of 686 points and they
show amazing repeatable detail.

Can you post the files?

Sure, what files are are you interested in

Here is a picture of the chart I made from the CSV file and the Curve0.dat with first 68 points entered manually.
It will not let me post a .dat file so here is a screen capture.

Post the CSV or dat files.  Just change the file extension to txt on the latter

collected X Axis Scale data every 1mm

Curveo.dat