NY Land Surveyor cheat sheet

Retracement priority: calls for natural monuments generally control over artificial monuments, courses and distances, and area; the objective is to locate the original boundary, not to create a new one.

Deed construction: read the entire deed and adjoining deeds together; specific calls usually prevail over general calls, and an unambiguous deed generally needs no extrinsic evidence.

Senior rights: where deeds overlap, the earlier conveyance generally has priority in the overlap, subject to recording acts, estoppel, adverse possession, and later valid agreements.

Adverse possession in New York: RPAPL Article 5 generally sets a ten-year period; the 2008 amendments changed required elements and presumptions, so each claim requires current statutory analysis.

Accretion and avulsion: gradual, imperceptible accretion belongs to the riparian owner; a sudden avulsion does not move the boundary.

Water boundaries: in New York, tidal boundaries generally run at mean high water; deeds bounding non-tidal streams normally extend to the thread or centerline unless excluded.

Practical location: a long-acquiesced line may fix a boundary when the parties clearly intended it and treated it as the line; mere occupation without intent is usually insufficient.

Easements versus boundaries: an easement grants use rights, not title; a boundary line agreement can resolve uncertainty but cannot convey title unless deed formalities are met.

Monument preservation: original monuments, even if disturbed, are evidence; retracement should restore or reference them and document ties and occupations.

EDM specification: accuracy stated as ±(a mm + b ppm) gives approximate error a + bD/1000 mm, where D is distance in meters and b is parts per million.

Atmospheric correction: 1 ppm equals 1 mm per km; apply the instrument's temperature-pressure correction or the prescribed ppm value to observed distances.

Traverse closure: linear misclosure = sqrt(Δlatitude² + Δdeparture²); relative precision = misclosure divided by perimeter, expressed as 1:N.

Angle sets: observe direct and reverse positions and average to cancel collimation and some axis errors; close the horizon to 360 degrees as a check.

Differential leveling: height of instrument = known elevation + backsight; unknown elevation = height of instrument − foresight; compare misclosure to allowable.

Curvature and refraction: combined correction is approximately 0.0675 K² meters for sight distance K in kilometers; apply for long sights.

GNSS RTK: an integer-fixed solution is typically centimeter-level; check PDOP, use redundant observations, and do not rely on RTK alone for boundary evidence.

Tape corrections: temperature correction Ct = L α (T − T0); tension and sag corrections are applied with their proper signs.

Height relationship: ellipsoidal height h = orthometric height H + geoid undulation N; therefore H = h − N, with signs checked for the geoid model convention.

Combined scale factor: CSF = projection scale factor × elevation factor; grid distance = ground distance × CSF.

New York State Plane has four Transverse Mercator zones-Long Island, East, Central, and West; coordinates are mapping products, not title boundaries.

Grid convergence: the angle between grid north and true north; grid azimuth = true azimuth − convergence, with the sign verified for the local convention.

Datums: NAD83(2011) is horizontal and NAVD88 is vertical; do not mix with NAD27 or NGVD29 without a documented transformation.

Control hierarchy: tie GNSS vectors to published passive marks or CORS; OPUS processes static observations against CORS and depends on duration and geometry.

Elevation factor: EF ≈ R/(R + H), where R is Earth radius and H is ellipsoid height; EF is close to 1 near the ellipsoid.

State Plane scale factor increases away from the central meridian; record both ground and grid distances and state the basis of coordinates.

Scale: a representative fraction 1:N means one map unit equals N ground units; larger N means a smaller-scale map with less detail.

Aerial photo scale: S = f/H, where f is focal length and H is flying height above ground; use consistent units and account for terrain elevation.

Relief displacement: d = r h/H, where r is radial distance from the principal point, h is object height, and H is flying height.

Aerial overlap: about 60 percent endlap and 20 to 30 percent sidelap are common for stereo mapping and DEM production.

Orthophoto: an image corrected for relief displacement and camera tilt; it has uniform map scale but is not by itself a boundary survey.

LiDAR products: a DSM includes vegetation and structures; a DTM represents bare earth after filtering, so classification quality controls accuracy.

Remote sensing resolutions: spatial, spectral, temporal, and radiometric resolution describe different limits of an imaging system.

NSSDA accuracy: horizontal 95 percent accuracy = 1.7308 × RMSE_r; vertical 95 percent accuracy = 1.9600 × RMSE_z.

Contours: a constant contour interval shows steep terrain by closely spaced lines; check source scale and vertical datum before using elevations.

Latitude = distance × cos(bearing); departure = distance × sin(bearing); in a closed traverse, adjusted sums should equal zero.

Area by coordinates: Area = ½ |Σ(X_i Y_{i+1} − X_{i+1} Y_i)| for coordinates listed in order around a closed polygon.

Least squares: minimize Σwv²; weights are commonly inverse variances; reference variance uses Σwv² divided by redundant observations.

Error propagation: for independent observations, variances add after multiplication by partial derivatives; correlated observations require covariance terms.

Weighted mean = Σ(w_i x_i)/Σw_i; use inverse-variance weights when observations have different precision.

Circular curve: T = R tan(Δ/2); L = RΔ in radians; LC = 2R sin(Δ/2); M = R[1 − cos(Δ/2)]; E = R[sec(Δ/2) − 1].

Vertical curve: K = L/A, where L is curve length and A is algebraic grade change in percent; K gives length per one-percent grade change.

Blunder detection: inspect misclosure, residuals, and redundant observations; a blunder should be found and removed, not distributed by adjustment.

Compass rule distributes misclosure proportional to traverse length; transit rule distributes proportional to latitude and departure magnitudes.

New York Education Law Article 145 and NYSED regulate land surveying; only a licensed land surveyor may practice land surveying or use the protected title.

Continuing education: New York land surveyors must complete 24 professional-development hours per triennial registration, including at least one hour of professional ethics.

Seal and signature: a licensee must seal and sign surveying maps, plans, and reports prepared under responsible control; sealing uncontrolled work is unprofessional conduct.

Unprofessional conduct includes negligence, incompetence, false or misleading statements, and practicing beyond one's competence.

Standard of care: the skill and care ordinarily exercised by reputable land surveyors in similar circumstances; it is not a warranty of perfect results.

Conflict of interest: disclose financial or personal interests that could affect judgment and avoid compensation contingent on a boundary opinion or regulatory outcome.

Boundary survey versus title: a survey locates monuments, occupation, and deed lines; it does not determine title, which is a legal conclusion.

Documentation: retain field notes, calculations, research, and the basis for opinions; clear records support professional defense and later retracement.

Advertising and representations: do not make false, misleading, or deceptive claims; include license information where required on professional documents.