LA Land Surveyor common mistakes
LA Land Surveyor · Understand the traps and how to avoid them.
Treating the record (map) bearing and distance as controlling over the monument called for, and accepting a found monument only when it matches the record within a tight tolerance.
Candidates learn coordinate geometry and least squares first, so they reflexively rank numeric closure above evidence hierarchy. They forget that California follows the common-law rule that monuments control over courses and distances, and that a call for a monument can be satisfied by a monument of the kind called even if its position differs from the record measurements.
What to do instead
Before touching a calculator, write out the evidence hierarchy for the specific problem (natural monument, artificial monument, lines/adjacent boundaries, courses and distances, area, coordinates) and state which element the question is testing. Practice problems where the record distance and the found monument conflict, and articulate in writing why the monument prevails and what would defeat it (e.g., the monument is not the one called for, was moved, or is a later uncalled-for monument).
Applying proportional measurement or proration of excess/deficiency across an entire subdivision without first determining whether an original monument exists at the point in question, and without distinguishing original from subsequent surveys.
Proration is the most heavily drilled computational technique in review courses, so candidates reach for it as a default. They miss the threshold question: proration is a rule of last resort, applied only where monuments are lost, and only within the lines actually controlled by the original survey.
What to do instead
Build a decision checklist: (1) Is the corner original, lost, or obliterated? (2) If lost, is there a record that reliably reestablishes it? (3) Only if genuinely lost, prorate, and only between the nearest existent original corners on that line. Work several problems where proration is the wrong answer and identify the correct controlling evidence instead.
Confusing the hierarchy of written versus unwritten rights: assuming adverse possession, prescriptive easements, or boundary by agreement/acquiescence can be analyzed the same way as record boundary location, or ignoring that these are separate legal doctrines with different elements and different proof burdens.
Boundary retracement and title doctrines are taught in separate courses, and candidates blend them. California's requirements (e.g., payment of taxes for adverse possession claims, the elements of acquiescence and agreement, and the effect of the Marketable Record Title Act) are fact-specific and easy to half-remember.
What to do instead
Make a one-page comparison chart of each doctrine with its elements, the burden of proof, and the tax requirement, and attach a short fact pattern to each. When a question mentions long occupation, ask explicitly whether the issue is location of a record boundary or acquisition of title, and answer only the question asked.
Treating State Plane coordinates, geodetic bearings, and ground distances as interchangeable, and failing to apply scale factor, convergence, and elevation (combined) factors when converting between grid and ground.
The arithmetic is simple but the conceptual chain is long, and candidates memorize one formula (grid = ground × combined factor) without tracking direction, the distinction between the two components of the combined factor, or that convergence rotates grid north away from true north.
What to do instead
Practice a full worked conversion in both directions for a specific zone and elevation, labeling each step: ground distance to ellipsoid (elevation factor), ellipsoid to grid (scale factor), then grid to ground. Sketch the meridian convergence angle and state which way to rotate. Verify with an order-of-magnitude check: combined factors in California are typically within a few parts per 10,000 of unity, so a result differing by 1 percent signals an error.
Reporting a coordinate or boundary position without an accompanying statement of accuracy, datum, epoch, and adjustment, or quoting a coordinate to more decimal places than the survey supports.
Software outputs eight decimal places and candidates copy them. They also conflate NAD83 (2011) with earlier realizations and ignore that active tectonic deformation in California makes epoch essential for high-accuracy coordinates.
What to do instead
Adopt a standing metadata template for every coordinate answer: datum and realization, epoch, projection and zone, units, adjustment/network, and positional uncertainty at a stated confidence. Round output to the precision the uncertainty justifies. Memorize the practical consequence: a coordinate without datum and epoch is not a coordinate in California.
Ignoring or misapplying instrument and atmospheric corrections: not applying prism constant, curvature and refraction, temperature/pressure correction to EDM, or mis-setting the total station's scale and angle-collimation checks.
Field procedures are learned on the job with the instrument's defaults, and exam questions isolate the correction the candidate never had to set manually. Sign conventions (prism constant added or subtracted) are a common trap.
What to do instead
Write the correction formulas from memory and apply them to a numeric example: first velocity correction from temperature and pressure, curvature and refraction (approximately 0.0675 K² with K in kilometers, refraction included), and prism constant sign. Know which corrections the instrument applies internally and which the surveyor must apply, and check what the instrument manual states for the specific model family.
Confusing accuracy with precision, and misreading the meaning of a misclosure or residual: reporting a loop misclosure as an accuracy statement, or treating a small standard deviation as proof of correctness.
Statistical vocabulary is used loosely in practice, and candidates do not separate random from systematic error. A tight cluster of observations can be precisely wrong if a systematic error (e.g., an unmodeled scale error or a mis-set prism constant) is present.
What to do instead
For each problem, classify the error as blunder, systematic, or random, and state which statistic addresses it. Know that misclosure is a check on internal consistency, not on absolute accuracy, and that least squares gives the most probable value under stated assumptions, not the true value. Practice computing a standard deviation and a standard deviation of the mean and explaining the difference in one sentence.
Treating photogrammetric or remotely sensed positions as equivalent in evidentiary weight to a field survey, or accepting a DEM/orthophoto-derived elevation or boundary without checking resolution, accuracy specification, and datum.
Mapping products look authoritative and are easy to measure on screen. Candidates forget that National Map Accuracy Standards and newer accuracy statements are expressed at a specific confidence level and that horizontal and vertical accuracies differ substantially.
What to do instead
Attach to every mapping product the questions: what is the horizontal and vertical accuracy at what confidence, what is the ground sample distance or pixel size, what datum and epoch, and what is the source (imagery, lidar, radar)? Know the difference between relative and absolute accuracy and when each matters for a boundary or construction purpose.
Answering Subdivision Map Act questions from general planning intuition rather than the specific statutory framework: confusing a tentative map with a parcel map, missing the distinction between a final map and a parcel map, or overlooking the local ordinance and conditions of approval that fill in the statutory gaps.
The Act sets a framework and delegates much to local ordinance, and candidates study the code sections without connecting them to the local approval process. Time limits, expiration, and the effect of filing also get muddled.
What to do instead
Build a table with columns for tentative map, parcel map, and final map: when each is required, approval authority, statutory time limits, expiration and extension provisions, and what must appear on the map. Then add a column for what the local ordinance typically adds (dedications, improvements, fees). Verify current statutory time limits against the current code text, since these have been amended.
Confusing map projection and coordinate choices in GIS with legal boundary geometry: assuming a GIS parcel layer represents the legal boundary, or failing to account for projection distortion, datum shift, and topology when overlaying or measuring areas.
GIS tools measure and overlay without warning, and candidates trust the output. They forget that a parcel layer is a cartographic representation, that area computations differ by projection, and that datum transformations introduce shifts that matter at boundary scale.
What to do instead
State the projection, datum, and units before any area or length computation, and know that equal-area projections preserve area while conformal projections preserve local shape and angles. Treat GIS parcel data as an index to the record, never as the record. Practice identifying when an overlay discrepancy is a datum issue versus a genuine boundary conflict.