Traverse Adjustment

Tools – Adjust – COMPASS ADJUSTMENT

This function is used to get closure information, balance angles and verticals, and do a compass adjustment.  To perform an adjustment, each traverse point must have a description that starts with TR (in uppercase, followed optionally by any other characters), and be collected in order. Sideshots can be shot in any order from any points. The way the reference bearing is entered depends on the type of traverse:

Closed loop with internal reference:
Closed loop with internal reference

The reference bearing for this type of traverse lies along one of the legs of the traverse. The closing reference bearing is 180 degrees from the starting reference, and the closing point is the same as the starting point.

Closed loop traverse with external reference:
Closed loop traverse with external reference

In this case, the reference is not one of the legs of the traverse. When closing, turn the final angle to the reference and enter a zero distance to a dummy point number (point 6 above). The closing reference bearing is the same as the starting reference bearing, and the closing point is the same as the starting point.

Traverse between two known points:
Traverse between two known points

In this case, a reference bearing is entered at both the starting and closing points of the traverse. When closing, turn the closing angle to the reference bearing and enter a zero distance to a dummy point number. (The dummy point is 6 in the above drawing, 7 is the actual closing point some small distance from 5).

Open traverse:
Open traverse

This type of traverse starts at a known point and has a known starting reference bearing, but does not close on a known point or have a known closing reference bearing.  This type of traverse you cannot adjust so you don’t need this function since coordinates were already computed as you collect.

The following prompts appear:

Closing point#:

Enter the closing point#.  In a loop traverse, this will be the same point# as the first setup point.  In a point to point traverse, this can be any point.  If the coordinates have not been previously stored, the program will ask for the coordinates of the point.

Closing Reference Bearing:

Enter the closing reference bearing, which is the direction of the last foresight.  The starting reference bearing plus 180 degrees will be displayed.  This is for convenience when doing a closed loop traverse with internal reference.

Select angle or bearing code:

Press the button for the quadrant of the bearing.

Closing Line: 45.5000 SE  0.047
Distance Traversed:  1832.412
Precision:
1:38953

The program displays the closing line bearing and distance, the total distance traversed, and the precision of the traverse.  Press OK.

Angular Error 0.0010
Balance Angles?

The program displays the angular error.  Press Yes to balance the angles equally to all legs of the traverse, or No to use no angular balance.

Vertical Closure:
0.127
Balance verticals?

The program displays the vertical closure error. (If computing elevations.)  Press Yes to balance the vertical error proportionate to the length of each shot, or No to use no vertical balance.

If you balanced the angles, the program displays new closure information after re-computing the traverse with the balanced angles.  Press OK.  Then the program re-computes all the points applying the selected adjustments to the points. The program writes a copy of all the traverse closure information to a file called printout.txt which can be printed back in the office for your records.

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