NM Land Surveyor common mistakes
NM Land Surveyor · Understand the traps and how to avoid them.
Treating a found monument as conclusive evidence of the boundary line without checking it against the record plat, field notes, and adjoining deeds, and without evaluating whether it is the original corner or a later replacement.
Candidates memorize 'monuments control over distances' as a slogan and apply it mechanically. New Mexico retracement practice requires identifying the character of the monument (original, perpetuated, or counterfeit), its positional history, and whether record evidence corroborates it. A disturbed or reset stone can be evidence of a line without being the controlling corner.
What to do instead
Before accepting any monument, build a monument file: when set, by whom, how described in the original GLO/SLO notes or plat, whether the physical description matches (size, markings, witness trees, accessories, mound of stone), and whether it is undisturbed. Compare it to the record bearing and distance and to the adjoining ownership. Where evidence conflicts, rank it: original undisturbed monument, then original evidence of the monument (pits, mounds, accessories), then perpetuated monument, then record measurements, then area. Practice writing a one-paragraph monument analysis for each corner in a sample retracement.
Applying modern subdivision or plat bearings and distances to interpret a GLO/SLO original survey, or assuming the original survey lines were run on true north with modern precision.
Candidates carry over habits from lot-and-block work, where record bearings govern, into PLSS retracement, where the original surveyor's compass work, variation, and methods (and the 1855 and later New Mexico surveys) are the controlling evidence. They also forget that many New Mexico GLO surveys predate modern standards and contain closure errors, fractional lots, and meander lines.
What to do instead
Study the instructions in force at the date of the original survey and the field notes themselves. Convert and check bearings for magnetic variation and instrument error. Distinguish meander lines from boundary lines and treat meander lines as approximating the water boundary, not as the boundary. Recompute the original survey's closure and note its error before comparing to modern measurements, so you do not 'correct' original lines into nonexistence.
Confusing the different corner types and their rules - standard corners, closing corners, quarter-section corners, meander corners, and witness corners - and applying the wrong proportioning rule when a corner is lost.
The PLSS has a family of corner types each with its own establishment rule and its own restoration rule. Candidates learn a single 'single proportionate measure' or 'double proportionate measure' formula and apply it indiscriminately, or they treat a closing corner as if it controlled a line it was only meant to close upon.
What to do instead
Build a decision table: for each corner type, list how it was originally established, what evidence establishes it, and which restoration method applies (single proportionate for a lost corner on a line between two existent corners; double proportionate for a lost corner at the intersection of two lines; grant boundary rules where applicable; special rules for closing corners and meander corners). Work several lost-corner problems end to end, including the field evidence you would seek, and verify your proportioning by checking that the restored position is consistent with all controlling corners.
Missing the New Mexico-specific statutory layer: assuming the federal PLSS rules alone govern, and ignoring state requirements for corner recordation, plat content, surveyor licensure scope, and county recording.
Candidates study national PLSS material and generic boundary law, then arrive at state-law items without having read New Mexico's surveying statutes and board rules. New Mexico's land tenure history - Spanish and Mexican grants, the Treaty of Guadalupe Hidalgo, and the Court of Private Land Claims - also creates categories of boundary that do not behave like PLSS sections.
What to do instead
Read the New Mexico surveying statute and the Board of Licensure rules directly, and outline them into a one-page checklist: who may survey, what a plat must show, corner recordation and filing timelines, county clerk recording, and monument preservation duties. Separately, outline how Spanish and Mexican land grants were confirmed and how their boundaries are retraced (often by grant documents and natural monuments, not PLSS rules). Test yourself by writing the checklist from memory, then checking it against the statute.
Mixing coordinate systems and datums - reporting New Mexico State Plane coordinates in the wrong zone or projection, comparing NAD27 to NAD83 coordinates without transformation, or treating grid azimuth as ground azimuth without scale and convergence.
Candidates compute coordinates in software and trust the output, forgetting that New Mexico has multiple State Plane zones and that grid-to-ground differences (scale factor, convergence angle, elevation factor) can exceed the precision of the survey. They also forget the epoch and realization of NAD83 and how to transform legacy data.
What to do instead
For every coordinate-based problem, write down the datum, realization/epoch, projection, zone, and units before computing. Practice converting grid to ground: apply combined scale factor and convergence, and show the arithmetic. Learn the difference between geodetic, grid, and ground azimuth and be able to state which one belongs on a plat. For legacy data, identify the transformation (e.g., NADCON) and its stated accuracy rather than assuming equivalence.
Reporting a measurement or adjustment to more precision than the observation supports, or misapplying least squares - e.g., treating correlated GPS baseline observations as independent, or using an unweighted adjustment when observation quality varies.
Software outputs many digits and candidates copy them onto plats and into reports. They also treat all observations as equal-weight because the adjustment runs regardless, ignoring that GPS vector components are correlated and that leveling and total station observations have different error characteristics.
What to do instead
Carry a precision policy: report to the number of digits justified by the weakest controlling observation and by the stated accuracy standard. Before adjusting, list each observation with its a priori standard deviation and note correlations for GPS vectors. Run the adjustment, then examine residuals and the reference variance; a reference variance far from 1 signals misweighted observations. Be able to explain why correlated baselines require the full covariance matrix rather than scalar weights.
Drafting a subdivision plat or easement description that is internally inconsistent - closure error not disclosed, area not matching the lot lines, bearings and distances not forming a closed figure, or an easement described by a centerline width that does not match the drawn boundaries.
Candidates focus on the drawing and the narrative and skip the arithmetic check. Plat and description standards require mathematical closure, stated basis of bearings, and consistency between the tabulated data and the graphic. Easement descriptions that give a centerline and a width must produce boundaries that actually lie at that offset.
What to do instead
Adopt a closure and consistency protocol: close every boundary by coordinates and by bearings/distances, report the misclosure and how it was distributed, verify tabulated areas against computed areas, and check that every easement's stated width matches the offset boundaries. Before submitting, read the plat as a stranger would and confirm that the basis of bearings, datum, units, and monument ties are all stated. Practice on a sample plat by inserting a deliberate error and finding it.
Assuming a topographic or construction survey is complete because the points were shot, without verifying datum, control, and the deliverable's stated accuracy - or failing to check that construction staking matches the plan's design intent.
Field production feels like progress, and candidates equate data collection with a finished survey. They also skip the pre-stake plan check, so a plan error (wrong elevation datum, conflicting dimensions) is staked into the ground and discovered later.
What to do instead
Use a written checklist for each deliverable: control established and checked, datum and units stated, vertical datum identified (NAVD 88 vs. assumed), accuracy standard stated and verified by a check shot or redundant observation, and a plan-review step that reconciles dimensions, elevations, and datum before staking. For construction, verify a known point and a known elevation on site before staking, and document the check.
Accepting a photogrammetric or remote-sensing product at face value - using an orthophoto or LiDAR surface as if it were a survey-grade boundary or elevation source without checking resolution, horizontal and vertical accuracy, and datum.
These products look authoritative and are easy to measure on. Candidates forget that orthophoto positional accuracy, LiDAR point spacing, and surface-model vertical error are stated in metadata and may be far coarser than a boundary or design survey requires, and that imagery does not establish legal boundaries.
What to do instead
For every imagery or point-cloud product, read the metadata: acquisition date, resolution or point density, stated horizontal and vertical accuracy, datum, and processing level. Compare the stated accuracy to the required tolerance and reject the product if it cannot meet it. Never derive a boundary from imagery; use it only as supporting evidence. Practice by taking a sample product's accuracy statement and computing whether it meets a given design tolerance.
Overlooking professional-practice and records obligations: no written contract or scope, no error-and-omission coverage check, no documentation of monument preservation or corner recordation, and no retention of field notes and computation files.
Candidates treat these as administrative afterthoughts and focus on technical content. But the exam tests the licensee's duties - scope of care, contracts, records retention, reporting obligations, and safety - and these are easy points lost to unfamiliarity.
What to do instead
Build a practice-management checklist covering: written agreement and scope, standard of care, insurance and liability exposure, records retention and file documentation, monument preservation and corner record filing, and statutory reporting. Pair it with a safety checklist for field work (traffic control, utility locating, heat and remote-area precautions, which matter in New Mexico). Review the Board's rules on these topics and be able to state the specific obligation and deadline, not a general impression.