Bowditch rule is applied to A. an open traverse for graphical adjustment B. a closed traverse for adjustment of closing error C. determine the effect of local attraction D. none of the above

The correct answer is: A. an open traverse for graphical adjustment.

Bowditch’s rule is a method of adjusting the angles of a traverse by minimizing the sum of the squares of the errors. It is used for open traverses, which are traverses that do not close on themselves. The rule is applied by first calculating the closing error, which is the difference between the sum of the interior angles of the traverse and 360 degrees. The closing error is then divided by the number of sides of the traverse to get the average error per side. The average error per side is then used to adjust the angles of the traverse.

The other options are incorrect because:

• B. A closed traverse is a traverse that closes on itself. The closing error for a closed traverse is always zero, so Bowditch’s rule is not needed.
• C. Bowditch’s rule is not used to determine the effect of local attraction. Local attraction is the effect of a nearby object, such as a large metal object, on the magnetic field. The effect of local attraction is determined using a compass and a clinometer.
• D. None of the above is the correct answer.