Field Track: Field Procedures, Equipment, and Measurement Fundamentals
What the field track tests
The Field Track covers the working knowledge a survey technician applies in the field: instrument setup, measurement technique, field notes, and safe, defensible data collection. Expect questions on leveling, angle and distance measurement, instrument care and calibration, and the difference between random and systematic error.
Core concepts to master
- Instrument setup: tribrach leveling with the circular and plate (tubular) bubbles, optical plummet or laser plummet centering, and forced-centering on a tripod. Know that the plate bubble is more sensitive than the circular bubble and is used for fine leveling.
- Leveling: differential leveling, backsight/foresight, height of instrument (HI), turning points, and closure checks. Distinguish a bench mark from a turning point.
- Angles and distances: horizontal vs. vertical angles, zenith angle, and the difference between slope, horizontal, and vertical distance. Know that EDM measures slope distance and that a prism constant offsets the measurement.
- Errors: systematic (instrument/prism constant, refraction, temperature) vs. random (pointing, reading). Mistaking one for the other is a favorite trap.
Traps that appear in questions
- Confusing HI with elevation of a point. HI = established elevation + backsight reading.
- Forgetting that a foresight is subtracted from HI to get the new elevation.
- Assuming a level loop needs no closure check; every loop should close back to a known point.
- Mixing up the circular bubble (rough leveling) with the plate bubble (precise leveling).
Worked example / rule of thumb
Bench mark elevation 100.000 ft. Backsight reading 4.250 ft gives HI = 104.250 ft. A foresight of 6.100 ft gives that point's elevation = 104.250 − 6.100 = 98.150 ft. Rule of thumb: HI = known elevation + backsight; new elevation = HI − foresight. Always carry the check: sum of backsights minus sum of foresights should equal the elevation change over a closed loop.