2. Closure
On a closed loop traverse, the sum of the Lats should equal zero as should the sum of the Deps.
Closure condition:


Figure D7 Perfect Closed Loop 
Most traverses wonâ€™t close perfectly due to the presence of errors. If the field crew followed careful procedures and compensated distance measurements for atmospheric conditions, only random errors prevent achieving perfect closure:event achieving perfect closure:
Actual closure:


Figure D8 Cumulative Random Errors 
Figure D9 Linear Closure 
The Linear Closure, LC, is the total misclosure distance. It is computed from the Lat and Dep errors:
Equation D7 
Traverse precision is a function of the linear closure and the total survey distance. The precision is stated as a relative value, usually as 1 unit of error per D units measured:
Equation D8 
What is allowable minimum precision? It depends on the survey purpose. Traditional first order surveys have a required precision of 1/100,000; in Wisconsin a property survey must be at least 1/3000. In order to achieve a formal minimum precision, specific equipment and field procedures must be used which match that precision requirement. Achieving a minimum precision should be by design not by accident.