The boss of a crew surveying land; the party chief is responsible for the accuracy of a survey. The party chief keeps meticulous notes on every aspect of the survey so that any errors can be backtracked to the source. The party chief assigns duties and plans the work of the other members of the survey party.
Most states have a program for taking tests to become a licensed public surveyor (called various things in various states). Most surveys used for official purposes (eg, conveying land), must have the seal of a licensed surveyor on them. Sometimes the licensed surveyor is the party chief, but more often the party chief works at the direction of the licensed surveyor.
See: land surveying.