Hello,

I am using ArcMap 10.4.1.

My question does not pertain directly to ArcMap, but to an excel 3d similarity transformation calculator I am attempting to develop. I am using a decent text reference (Datums and Map Projections, by JC Iliffe) that gives me 4 of the matrix (vector) relationships but, beyond setting the provisional values to zero as a first approximation, I am unclear what additional assumptions are being made to solve all the variables such as rotations about each axis, lambda, etc.. My example is not a 3d Helmert 7 parameter type, which I would actually prefer. So I have to ask, does anyone have a 3d Helmert 7 parameter transformation example that has a little more detail beyond the first assumption to assist in solving?

If I still had my least squares textbook from grad school, I'd send it to you!

I follow a surveyor's forum and they've discussed least squares a few times. I think you can access the threads without having a login. It's not a big deal if you do decide to create a login. It's a personally run website, and they won't spam you. For instance,

Least squares spreadsheet

Getting Started with Least Squares

They're not doing the same problem as they're solving for traverses, etc. but you certainly may find some references to code or good textbooks.

Melita