SurvCE Mixing Total Station and GPS Observations at Grid

Usually you mix Total Station data with GPS at Ground. Is is possible to mix data at Grid? What are the advantageous of using a single scale factor vs. using automatic scale factors for each optical shot?

[@lztoniolo]

Mark, you're such a great human! Thanks for sharing your knowledge and I hope you keep it coming and posting these videos. I miss your videos so much!!! Hope you make some videos about Landstar 8. Much love from Brazil.

[@fielddog8111]

You're saying match ground distances (TS) with grid distances (GNSS) by using a SF for each TS setup. Most of our jobs use control points set by RTK and are less than a thousand feet apart. In fact, most are about five hundred feet apart. In the later, we sometimes get as much as a 0.10' difference in distance between RTK and TS. I can't say how much of that difference could be attributed to poor satellite geometry or SF. I believe Topcon MAGNET Field sets its own SF based on the Florida SPC East zone. I'm unsure if that SF is a constant, or if it changes with the position of the RTK rover. Most of our work involves staking right-of-way lines for sidewalk construction or staking drainage easements. Sometimes we perform long route surveys for our engineers. We don't select the Grid to Ground checkbox in MAGNET Field. Would that correct the distance discrepancy that I mentioned?

[@MarkSilver]

I purposely chose the location in this video to be a project with LOTS of elevation difference and long distances. For short distances, at low ellipsoid heights this may not be a big deal. There are two ways to fix the difference in the field: bring the GNSS job to ground (Single Point Localization, Grid to Ground) or bring the optical measurements down to Grid (Ground to Grid). I don't know about Magnet, but I assume it has both a Grid-to-Ground and a Ground-to-Grid. I suspect the answer to which to use is 'it depends' (the universal survey answer.) I am predisposed to think that for a big project with large elevation changes, it is probably best to bring everything down to Grid. If for no other reason than it might be hard to choose a project base and elevation.