NCEES PS (Principles and Practice of Surveying) Exam
What the PS tests
The PS exam targets professional-level judgment rather than routine computation: boundary and legal principles, control and geodetic surveying, mapping, GIS and photogrammetry, and professional practice. Many items are scenario-based, asking which evidence or standard governs when record data and field data conflict.
Core rules
- Boundary evidence hierarchy. Natural monuments, then artificial monuments, then courses and distances, then area - unless a call is plainly erroneous or a senior right controls. Acquiescence, adverse possession, and unwritten rights can override record lines.
- PLSS. Section 1 sits in the northeast corner of a township; numbering runs west to 6, south one row, then east to 12, and so on. North and west tiers of sections are fractional and produce double corners.
- Geodesy. NAD83 is the horizontal datum and NAVD88 the vertical datum; NGVD29 is legacy. Grid distance = ground distance × combined factor (elevation factor × scale factor).
- Photogrammetry. Photo scale = f / H, where H is flying height above the ground or datum; relief displacement grows with distance from the principal point.
Worked example
An original plat shows Lot 4 with 100.00 ft of frontage in a block measuring 500.00 ft. The block corner monuments survive but the lot corner is lost; the block now measures 500.60 ft. Proportionate frontage = 100.00 × (500.60 ÷ 500.00) = 100.12 ft, set from the controlling corner. Proportionate measurement restores the lost corner; it is improper where original monuments exist or where a senior boundary governs.
Traps
- Using area to fix a boundary when monuments are available.
- Mixing NAVD88 and NGVD29 elevations in a single adjustment.
- Reporting GPS-derived ground distances without applying scale and elevation factors to reach grid.
- Assuming UTM and State Plane are interchangeable, or using the wrong zone.
- Omitting ALTA/NSPS Table A optional items from the scope of work.