Traverses
 Fieldwork In Traversing
 Control By Traversing
 Angular Closure
 Linear Closure
 Adjustment Of Traverses
 Function Of Traverses
 Missing Data
 Bearing And Distance Of
    One Line
 Bearing Of One Line,
    Distance Of Another
 Lengths Or Bearings Of
    Two Lines

Angular Closure

The sum of the internal angles of a polygon (traverse) is given by the rule:

where n is the number of sides of the traverse, and a is each internal angle. Any variation from this sum is known as the misclosure and must be accounted for, either through compensation (if it is an acceptable amount) or elimination by repetition of the observations. An angular closure is computed for traverses performed with either theodolites or magnetic compasses. A larger misclosure could be expected when using a magnetic compass, but in any case it must be calculated and removed. The reduction of magnetic compass bearings to angles also eliminates the effect of local attraction.