PS Surveying cheat sheet

Negligence requires four proven elements: a duty of care owed, a breach of that duty, causation (actual and proximate), and actual damages.

Standard of care is the degree of care and skill ordinarily exercised by reputable surveyors practicing under similar conditions in the same or similar locality.

Common-law dedication requires intent by the owner to dedicate land to public use plus acceptance by the public; statutory dedication follows the plat statute.

Adverse possession generally requires possession that is actual, open and notorious, exclusive, hostile, and continuous for the statutory period.

An easement by necessity arises when a parcel is landlocked following severance of common ownership and strict necessity existed at severance.

A licensee may seal and certify only work personally performed or performed by subordinates under the licensee's direct supervisory control.

A statute of limitations bars suit after a set period running from the negligent act or its discovery; a statute of repose bars suit after a fixed period regardless of discovery.

Contract formation requires offer, acceptance, consideration, capacity, and legality; acceptance must be communicated in the manner invited by the offer.

Boundary rights not appearing in the record may arise from practical location, acquiescence, estoppel, or parol agreement, and are termed unwritten rights.

Combined curvature and refraction correction: C&R = 0.0675 K squared (meters, K in kilometers), or 0.0206 F squared (feet, F in thousands of feet).

Orthometric height H = ellipsoid height h minus geoid separation N; N comes from a geoid model such as GEOID18.

Combined grid factor = grid (projection) factor times elevation factor; ground distance = grid distance divided by the combined factor.

Relative precision of a traverse = total perimeter divided by linear misclosure, stated as 1:N; larger N means better closure.

Angular misclosure is distributed equally among angles when all angles were turned with equal precision; weighted distribution is used otherwise.

PDOP describes satellite geometry for GNSS positions: lower is better, and PDOP of 6 or less is generally acceptable for RTK work.

Taping corrections: temperature Ct = 0.0000065 L (T - T0); tension Cp = (P - P0)L/(AE); sag Cs = -w squared L cubed/(24 P squared).

Precision is repeatability while accuracy is closeness to the true value; systematic errors bias results consistently and random errors tend to cancel.

An EDM derives distance from phase comparison of a modulated signal, and results require prism constant and atmospheric ppm corrections.

Area by coordinates: twice the area equals the sum of X times the difference of adjacent Y values, or the sum of Y times adjacent X differences.

Compass (Bowditch) rule: latitude correction for a course = -(total latitude error) x (course length / perimeter); departure corrections use the same proportion.

Transit rule distributes misclosure in proportion to the magnitude of each course latitude or departure rather than to course length.

Circular curve: T = R tan(D/2), L = R x D in radians, LC = 2R sin(D/2), M = R(1 - cos(D/2)), E = R(sec(D/2) - 1).

Degree of curve (arc definition) D = 5729.578/R with R in feet; chord definition uses D = 2 arcsin(50/R).

Vertical curve: K = L/A with A the algebraic difference in grades in percent; the high or low point lies at x = g1 L/(g1 - g2) from the BVC.

Prismoidal volume V = (L/6)(A1 + 4Am + A2); average end area gives V = L(A1 + A2)/2.

Least squares adjustment minimizes the sum of squared residuals and yields most probable coordinates with standard deviations and error ellipses.

Inverse computation: azimuth = atan2(dE, dN) and distance = square root of (dE squared + dN squared).

Order of evidence for conflicting calls: natural monuments, then artificial monuments, then courses and distances, then area.

A meander line is not a boundary; the boundary is the water body, with the thalweg used for navigable waters and thread of the stream for non-navigable.

Accretion (gradual, imperceptible) adds land to the riparian owner; erosion removes it; avulsion (sudden) leaves the old boundary unchanged.

Adverse possession requires actual, open and notorious, exclusive, hostile, and continuous possession for the full statutory period.

Double proportionate measurement restores lost corners between accepted corners by proportion along the line and, where needed, by latitude and departure.

GLO section contains 640 acres; numbering begins at the northeast corner and proceeds serpentine west then east across successive tiers.

Boundary by agreement or practical location requires uncertainty or dispute, an agreement by the parties, and performance or possession consistent with it.

A prescriptive easement requires use that is adverse, open and notorious, and continuous for the statutory period; exclusivity is not required in many jurisdictions.

Senior rights: where the same land is conveyed twice, the earlier valid conveyance generally prevails over the later one.

Scale 1:1,200 is larger scale than 1:24,000; a smaller denominator yields more detail over a smaller area.

A USGS 7.5-minute quadrangle covers 7.5 minutes of latitude by 7.5 minutes of longitude and is published at 1:24,000.

Contour interval is the constant vertical spacing between contour lines; closely spaced contours indicate steep slopes, and every fifth contour is an index contour.

State Plane zones use Lambert Conformal Conic for east-west trending zones and Transverse Mercator for north-south trending zones; both are conformal.

Base flood elevation on a FEMA FIRM is the water surface elevation of the one percent annual chance flood and governs floodplain construction requirements.

A subdivision plat typically shows boundary, lots, blocks, streets, easements, setback lines, dedications, owner's certificate, surveyor's certificate, and approvals.

ALTA/NSPS Land Title Surveys follow the current ALTA/NSPS standards with optional Table A items selected in writing by the client.

A variance relieves a hardship unique to a parcel and not self-created; a special or conditional use permit authorizes a listed use subject to conditions.

Ground distance is obtained by dividing grid distance by the combined factor, and grid distance by multiplying ground distance by the combined factor.