How to correct vertical error on station?

[Craig Davis]

I had to finish a survey that was started by our part time surveyor.

When I did the back sight to Station 1 from Station 2 I noticed that there was a 44mm error in the vertical. I did a side shot to the back sight so know the correct level difference between the 2 stations.

I could go into the raw file and adjust the Vertical Angle of the foresight (Station 2) to give it the correct elevation. He'd already done all of his pickup work from Station 2 so reluctant to redo it.

What's the easiest way to fix this error?

Thanks

Craig

[Richard Sands]

Adjusting the elevations in your surveying software may be easier. Just apply the difference to the relevant points.
That's how I'd most likely do it.

If you don't have that option you could go into Field Genius raws data and change the pole height or your instrument setup height by 44 mm to make it fit.
Then recoordinate the raw file in FG and it should correct your points.
I'd make a backup for safety sake.

That also assumes that's what the problem is and not an actual collimation error that is throwing you out.
I found I had actually turned off my compensators the other day. Thankfully soon twigged what was going on and they were back on.

Hope that helps.

[Ed Gasbarre]

I agree with Richard. If you are confident of the elevation difference and which points were affected, a simple elevation shift in MSCAD or whatever software you are using, would be in order. However, I would also check to another point or so to see if the vertical error is consistent before applying the shift in a copy of the original file.

[Craig Davis]

We import it directly in to Civil3D using a FBK file and the way it comes in doesn't allow us to change the height of the station and the points from that station will be adjusted as well (Well not that I know of).

I didn't even think of the simple pole height adjustment. I was expecting that I could just go in to the raw file and substitute a corrected station in there and it would adjust from then on.

Thanks for the advice guys. Much appreciated.

Regards

Craig