Surveying Principles and Practices Flashcards

In the Public Land Survey System, how many acres are in a standard section?

Answer: 640 acres

A standard PLSS section is 1 mile × 1 mile = 640 acres; a township contains 36 such sections.

What is the purpose of 'double centering' (double-direct) when turning angles with a total station?

Answer: To eliminate or detect errors caused by non-perpendicularity of the horizontal and vertical axes

Double centering turns the angle in both direct and reversed telescope positions; averaging the two readings eliminates systematic errors due to instrument axis misalignment.

Which of the following best describes a 'deed of trust' in the context of land records research?

Answer: A security instrument using real property as collateral for a loan

A deed of trust is a security instrument in which a borrower conveys title to a trustee to hold as collateral for a lender until the loan is repaid.

A surveyor must establish a point on a hillside using three-wire leveling. What is the primary advantage of this technique over single-wire leveling?

Answer: It provides a check on each rod reading and improves precision by averaging three stadia readings

Three-wire leveling reads the upper, middle, and lower crosshairs; the mean of the three readings reduces random errors, and the half-interval check detects blunders.

What does 'excess of sections' in the PLSS refer to?

Answer: The assignment of fractional lots larger than quarter-sections along the north and west township boundaries

Excess (or deficiency) from closing errors in a township is placed in the fractional lots along the north and west boundaries of the township, following GLO instructions.

What is 'total propagated error' (TPE) used for in precision surveying?

Answer: To estimate the combined effect of all identified error sources on the final measurement result

TPE combines individual error components (random and systematic) using root-sum-square or other methods to quantify the expected uncertainty of a final derived quantity.

When a surveyor sets an azimuth from a sun observation, what correction accounts for the angular radius of the sun's disk?

Answer: Semi-diameter correction

The semi-diameter correction adjusts for the fact that the observed limb (edge) of the sun is offset from its center by approximately 16 arcminutes, the sun's semi-diameter.