OR Land Surveyor common mistakes
OR Land Surveyor · Understand the traps and how to avoid them.
Computing a closed traverse's angular misclosure, distributing it, then reporting coordinates without checking the linear (position) misclosure against the allowed ratio before finalizing bearings and areas.
Candidates treat the angle adjustment as the whole closure check because angle work comes first and the adjusted angles look clean; the linear closure test requires a separate computation (departures/latitudes or inverse between start and end) that gets skipped under time pressure.
What to do instead
Build a fixed workflow: adjust angles, compute bearings, compute latitudes and departures, sum them, compute linear misclosure and precision ratio (e.g., 1:10,000), compare to the standard for the survey class, and only then compute coordinates and area. Practice it on a full traverse until the order is automatic.
Using a magnetic bearing from a record map or an old deed directly as a basis for a new survey without determining and applying the record-to-present declination or the difference between the record basis of bearings and true north.
Records often state bearings on an assumed or magnetic meridian, and candidates apply the number as if it were grid or true; the discrepancy is invisible until the parcel fails to close against adjoiners.
What to do instead
Always identify the basis of bearings stated on the record; if magnetic, compute the change in declination from the record date to the survey date using the annual change and apply it with correct sign, or better, hold the record bearings fixed and rotate to a monumented line. Verify by checking closure against adjoiners.
Mixing units or angle formats mid-calculation - decimal degrees entered where degrees-minutes-seconds are required, or state plane coordinates in US survey feet combined with metric distances - and carrying the error through to the final answer.
Calculators and software accept both formats silently, and the exam deliberately supplies data in mixed formats; candidates do not standardize before computing.
What to do instead
At the start of each problem, write the unit and angle format for every given value, convert everything to one system (usually decimal degrees and feet or meters) in a labeled step, and do a magnitude sanity check on the result before selecting an answer.
Treating a boundary retracement as a pure math exercise - accepting the record distances and bearings over the found monuments, or ignoring excess/deficiency in a senior conveyance when a junior parcel is described.
Candidates learn computation first and default to the numbers in the deed; the hierarchy of evidence (monuments over distances, senior rights, natural monuments over artificial) is tested as a judgment item and gets answered by arithmetic.
What to do instead
Before computing, list the evidence in priority order and state which controls. For junior/senior situations, determine the senior parcel first, then fit the junior description to the senior boundary and prorate the excess or deficiency along the junior lines. Practice with short fact patterns rather than full computations.
Computing a horizontal curve's elements (tangent, length, external, middle ordinate, chord) using the wrong degree-of-curve definition - arc definition versus chord definition - or applying a formula built for one to the other.
The two definitions give different radii for the same degree of curve, and candidates memorize formulas without tying them to the definition in use; highway problems usually imply arc definition while railroad problems imply chord.
What to do instead
Memorize the radius relations explicitly (arc: R = 5729.58/D; chord: R = 50/sin(D/2) in feet) and write which definition you are using at the top of every curve problem. Check by computing the radius both ways when the problem type is ambiguous and see which matches the given data.
Reading a contour map or topographic data set and reporting a slope, drainage direction, or cut/fill volume without first establishing the contour interval, horizontal scale, and the datum of the spot elevations.
Candidates jump to the formula (rise over run, average end area) and misread the vertical units or the scale, producing answers off by a factor of the interval or scale.
What to do instead
For every map-based item, first write down contour interval, map scale, and elevation datum. Compute slope as interval divided by horizontal distance between contours converted with the scale, and for volumes state the method (average end area, prismoidal) and confirm units before answering.
Performing a level loop or trigonometric leveling computation without applying curvature and refraction, or applying it with the wrong sign or magnitude, when sight distances are long.
The correction is small at short sights and candidates stop applying it entirely; when a problem gives long unbalanced sights, the omission changes the answer in the third decimal and the distractor is built on it.
What to do instead
Use the combined correction C = 0.0206 M squared (M in hundreds of feet, C in feet) or the metric equivalent, subtract it from the rod reading for curvature and refraction on long sights, and check whether the problem's sight lengths make it material. Note the sign convention in your formula sheet.
Ignoring the difference between grid and ground distances (combined factor, elevation factor, scale factor) and reporting or staking a ground distance where a grid distance is required, or vice versa.
State plane coordinates are grid-based and candidates treat them as ground measurements; the combined factor is often near 1.0 so the error looks negligible, but exam items are designed around it.
What to do instead
Whenever state plane coordinates or a projection is mentioned, apply the combined factor: grid = ground times combined factor, where combined factor = elevation factor times scale factor. Compute the elevation factor from the mean elevation and earth radius, and always state which distance you are reporting.
Answering boundary-law and easement questions from general intuition instead of the specific doctrine - adverse possession elements, prescriptive easement requirements, or the distinction between a boundary line agreement and acquiescence.
These are legal-reasoning items with no computation to anchor them, and candidates substitute everyday notions of fairness for the required elements (open, notorious, hostile, exclusive, continuous for the statutory period).
What to do instead
Memorize the element lists as checklists and test each element against the facts before choosing. For each doctrine, note the one element that most often fails (hostility or exclusivity for adverse possession, statutory period and adverse use for prescription) and look for that fact in the stem.
Skipping the final check on a computed answer - no verification that the area closes, that a bearing falls in the expected quadrant, or that a coordinate difference matches the stated distance - and selecting the first computed value.
Time pressure and confidence in the arithmetic lead candidates to move on; the exam's distractors are generated from common single-step errors, so an unchecked answer is likely to match one.
What to do instead
Reserve the last minutes for a verification pass: back-calculate distance and bearing from your coordinate differences, check that the sum of interior angles equals (n-2) times 180 degrees, and confirm the quadrant of each bearing against the sketch. If the answer is not among the choices, recheck units and angle format first.