Help Distributing Misclosure Error In A Level Survey

Hello all


I am very new to engineering and surveying in general. I have a problem which i am trying to understand and also solve.

I was wondering if there was anyone out there who could help explain how to distribute a misclosure error in a level survey.

I carried out a survey of a road. i used several TBMs and several change points. When i closed the survey i flew back using the same change points and ended back the survey on my original TBM.

My first TBM reduce level value was 10000, my second TBM reduce level value was 9378 and 3rd TBM was 8948.

When I fly back to close the survey I re-survey TBM3 and I got a reduce level of 8948, but when I re-survey TBM 2 I got a reduce level of 9379 (a difference of 1mm from the previous value) and my final TBM value I get a reduce level of 10005 a difference of 5.

How do you distribute the error, I simply do not understand the process of distributing the error. If someone could explain how you would distribute the error then that would help a great deal.

The issue i have is that i do not know over which change points i made the error (assuming that the error was as a result if misreading).

Attached is my survey data. I have higlighted which TBMs correspond to which.

Thanks

Thanks in advance