FBK file

[Anonymous]

hi ,

I am learning how to make a FBK file to calculate coordinates of stations in a traverse.

I have a problem with BS and AD syntax. BS command syntax is:  BS [point] (orientation)

i do not get the meaning of "orientation" . it is 0.00025 in this example. it should not be equal to azimuth?

can you please explain what is the meaning of orientation in BS syntax?

and why we need to add AD line (which its distance is NULL ) when we already observed AZ?

THANKS IN ADVANCE 

Examlpe (from a book) :

UNITS DMS
UNITS FOOT
SCALE FACTOR 1.00000000
NEZ 2 13740803.17650000 2156598.90520000 780.74000000 "B"
AZ 2 1 79.29000000

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! Station:2, Backsight:1
STN 2 5.07500000 ""
BS 1 0.00025000
SF 0.99986902
AD 1 0.00025000 NULL "A"
PRISM 4.77000000
F1 VA 1 0.00000000 563.03000000 90.39400000 "A"
F2 VA 1 180.00050000 563.02000000 269.20550000 "A"
F2 VA 3 257.10200000 315.71000000 268.43450000 "C"
F1 VA 3 77.10100000 315.71000000 91.16450000 "C"

[Mike.M.Carlson]

Hello,

A "BS" or "Back Sight" point is required to determine how the Total Station setup is orientated to the project-specific XY coordinate system.  "AZ" or azimuth refers to how you want to specify the north direction (it could be "assumed" or based on a known bearing related to the system).  Therefore, this may not equal the coordinate system orientation.  

[tcorey]

The BS Orientation is the reading from the horizontal circle of your total station. This is commonly set to 0, so that recorded angles are in relation to the backsight.

Your particular file appears to be setting a very small BS angle adjustment factor, as a well as a very small scale factor adjustment. It could be for adjustment from ground to grid. Ask a Land Surveyor that question.