I understand the process involved with transforming using the 2d similarity, or survey grid-ground methods, and I understand that the NAD27 is not a geocentric datum.?ÿ Some references indicate that there are several steps involved with transforming NAD27 to say NAD83 or to ITRF, and a few indicate that it is not possible.?ÿ Does anyone know what the workflow is to transform the NAD27 coordinates to one of the other common coordinate systems, assuming it is possible?
There is no direct mathematical relationship between '27 and '83 (whatever the flavor). There are tools (NADCON) that will provide approximate shifts, said to be accurate to around +/- 1/2 foot.
The workflow is now super simple with NCAT.
Same as always, you go to the field and locate them in the new system.
@mightymoe That would be the most accurate way.
Assuming you did it correctly.