I want to explore general discussion regarding methods and procedures for transferring or obtaining an elevation with a total station.
A prism pole height determination can be easily done by an actual measurement with a measuring tape. The height marks on the inner pole usually do not correspond to the measured height from the pole point to the center of the prism. Instrument height can be measured by a slope distance corrected to vertical distance. Data collectors and software are able to determine height of instrument from a remote point.
As primarily a boundary surveyor, I seldom utilize the third "z" ordinate. My data collector collects it anyway, and I typically use zero as both the HI and PH. However, sometimes I need to do topo work or a flood certification. The method that I use works for my equipment, and this discussion board always proves that there are other and sometimes better ways of doing things.
What are some methods that you employ when using a total station to obtain an elevation of a point by occupying a known x,y,z or shooting into a known point?
We always run vertical with our total station measure IH and RH and use trig to transfer the elevation. We always run vertical its a good check on your set up and you never know when the scope of the project may develop into in the future.
Measuring up from a known XYZ point, then shooting a second XYZ point as a check. I use a brick as a backsight (your basic brick) painted white, with a black horizontal line at 0.10 feet. Same for establishing a new XYZ control point. For most shots* I use a wood square with a line at 0.01 feet, sometimes a strip of masking tape with a 0.01' mark.
*Well, not most, since I use GPS for most shots.
:good:
"The height marks on the inner pole usually do not correspond to the measured height from the pole point to the center of the prism."
Most newer prism poles can be adjusted so that the marks will match by turning the bolt that holds the prism.
I use the 0 HI and O RH method. Double or even triple FS/BS. I always go from the reference BM to the newly set site BM and then back to reference BM using the new site BM as a reference. Just keep the rod at it's lowest position and use a bipod. I have always had good results with this method.
It doesn't matter what the rod height is so long as you are consistent. Instrument height is totally unimportant.
There's this:
https://www.profsurv.com/magazine/article.aspx?i=359
Good article.