Measurement and Computations
Core concepts
Candidates must be fluent in coordinate geometry, traverse computations, area by coordinates, and error propagation. Know latitude and departure, bearing conversions, inverse computations, and the closure ratio. Also understand significant figures and unit conversions.
Traps
Questions often test bearing quadrant conversions-converting an azimuth of 300° to a bearing of N 60° W. Another trap is the area-by-coordinates formula (shoelace), where a single sign error flips the result. Watch for closure ratio expressed as 1:N, where N is total distance divided by misclosure.
Worked example
A traverse closes with a linear misclosure of 0.10 ft over a total perimeter of 2,000 ft. The closure ratio is 2,000 / 0.10 = 1:20,000.
Rule of thumb
Azimuth to bearing: 0–90 = NE, 90–180 = SE, 180–270 = SW, 270–360 = NW, with the angle measured from the appropriate axis.