Orientate instrument using two unknown but accessible traverse points.
That is a way ,thanks Half bubble !
Do you have the other guys topo in CAD or only in paper or pdf? If you have it in CAD you can draw a line between the control points and query the line for the end point coordinates. Plug those into your tsc3 then resect using the control points or occupy one and backsight the other if possible.
OK , this thing is called free station .
It gives you the freedom to put the instrument wherever, calling the standing point 100,100,100 or 10 and orientate your instrument to one Control Point of the traverse , and foresight the next one.
This is how I understand it. But you actually are doing a resection. I just don't get what kind of transformation is involved between my arbitrary point or points in case I do this for a long - big project , and the lets say OSGB36 . 🙁
Gosh I hope I have got it right so far. Please let me know what do you think
Here's how I'd do it.
Set up inst. on arbitrary 50k/50k and set a nail there. Then, using a magnetic compass, observe the direction to one of the control stations, with a distance, reduced to horizontal.
Then, using that ctrl point as a backsite, I'd zero the inst on it. Then, turn angle to the other ctrl station, and measure the (reduced to horizontal) distance.
We can call the inst point A, the backsite B, and the fireside C.
Now, we have a triangle. With a bit of trig, we can compute line B-C. Let's say we find it to be N12ø13'14" E 822.56'.
Now, we go find the prev coord for these ctrl pnts. And, that the brg is N13ø15'20" E 822.60'.
We now rotate pnts A B and C so that line B-C matches the prev brg.
We now can make a mid point between B and C.
We also make a mid pnt between the original ctrl pnts.
We now translate points A B and C, and the mid point, so that the mid points of our control match the mid point of the control stations.
Now, my point is this. All the above is very normal for any surveyor. A standard exercise. Are you an engineer? Or, a student, or what?
Why do you come ask to borrow our every day tools, that we make a living with? Not that we are bothered by sharing, but if we have to spell this out for you, you just might be in water too deep for yourself....
He has the TOPO in CAD!
my way would be to open the cad file, have a look at both control points, make sure there is a simple 3D-point on each one, a line between both would be fine but not really necessary. Make sure the point name is as text readable and save as dxf to use it as map in Trimble Access on the tsc3.
on site use the resection station set-up, give your station the desired name (no assumed E,N,El), tape you HI., go to map view, select your first control point, switch to resection, in the name field for pointclouds shoot select the option ‘Select from Map’
since you already selected that one point it will be added for you’
repeat for second point
select calculate and you’ll be presented with the error values of your resectionand if ok with the E,N,El and your Azimuth, and you can start shooting other pointsin the same reference frame of your control points.
if you have all data digitally available use it digital and keep away from keying in manually! Humans make to many misstakes, computers don’t.