This is a two part question, but I'll try to start simple for step 1. We have multiple data sheets for County established control (some are also NGS) in the vicinity of our project. I was wondering, how would I transform these into ground coordinates for use in CAD? My problem is that each point has different scale factors, and combined factors. If a different scale factor is applied to each individual point, how do I define a Grid/Ground transformation across the entire job? Ultimately, we want to be able to use total station ground coordinates and base/rover RTK (State Plane Coordinates) in the same job. We are using MAGNET Field, a pair of Hiper V's, and two Topcon total stations (ES-103 & PS-103).
My automatic reaction is can't Magnet handle total station observations in State Plane?
The grid scale probably doesn't vary enough to get you in trouble if you just calculate an averaged factor at the center and scale up by it. The bugaboo would be if you have significant elevation changes and can't come up with a good averaged combined factor.
How large of a site are we talking? One PPM of scale error is only about a hundredth in two miles.
Yes. Magnet can apply the combined scale factor to EDM distances. CSF can be calculated by Magnet or an average CSF can be applied.
I recommend just working in state plane. But if you must scale to ground the thing to do is to select an average scale to use for the entire project. As long as the project is not over a few miles in extent everything will be fine. If the project is larger than that - well - that is what projection systems are made for.
Yes, I agree best to stay in SPC and learn how to work it properly.
