4. Summary

Forcing closure should never be done instead of closing a traverse using measurements or known endpoints. Being able to compute a missing line is no substitute for measuring it since errors can't be isolated. In the above example, if the length of line BC was mis-recorded as 514.95 instead of 541.95 that error won't be discovered but the traverse could still be forced to close. The length and direction of the closing line are dependent on, and absorb, all measurement errors and mistakes.