IN Land Surveyor cheat sheet

Priority of evidence in Indiana boundary retracement: natural monuments, artificial monuments, courses and distances, then area; written record evidence outranks a surveyor's later measurement.

An original government corner monument controls over a later resurvey position; a resurvey establishes evidence of the original location, not a new legal corner.

Adverse possession in Indiana requires 10 years of actual, open, notorious, exclusive, continuous, and hostile possession under a claim of right (Ind. Code 32-23-1-1).

Boundary by acquiescence requires a visible line treated as the boundary for at least 20 years in Indiana, with the adjoining owners' conduct showing mutual recognition.

A boundary line agreement (parol agreement plus possession) binds the parties and successors even when it departs from the deed line; reduce it to writing and record it.

Ambiguity in a deed is construed against the grantor; a call for a monument prevails over a call for quantity, and a specific call prevails over a general one.

Riparian boundaries on non-navigable streams follow the thread of the stream; on navigable waters the state owns the bed and the boundary is the ordinary high water mark.

Easements are non-possessory interests; a prescriptive easement in Indiana requires 20 years of adverse use, distinct from the 10-year adverse possession period for title.

Indiana requires a surveyor to file a corner record or monument record for public land survey corners and to set durable monuments at parcel corners per the board's rules.

NAD83(2011) and NATRF2022 are geodetic datums realized by a reference frame; a datum defines the relationship of coordinates to the Earth, a frame is the physical realization.

State plane coordinates in Indiana use the Transverse Mercator projection: Indiana East (FIPS 1301) and Indiana West (FIPS 1302), each with its own central meridian and false easting.

Grid to ground: ground distance = grid distance x (R / (R + h)), where R is the mean Earth radius and h is ellipsoid height; combined factor = scale factor x elevation factor.

Scale factor for a Transverse Mercator projection increases with distance from the central meridian; it equals 1.0 on the central meridian and grows east and west.

Geoid height N relates ellipsoid height h and orthometric height H by h = H + N; GNSS yields h, leveling yields H.

Ellipsoid-to-grid reduction uses the map projection (scale factor); grid-to-surface reduction uses the elevation factor derived from ellipsoid height.

A geodetic control network must have redundant observations; minimally constrained adjustment fixes one station and one azimuth, while fully constrained holds all fixed control.

Azimuth is measured clockwise from north; a grid azimuth differs from a geodetic azimuth by the convergence angle, which is zero on the central meridian.

Horizontal control accuracy is expressed by the NGS order and class standards; order defines the relative accuracy, class defines the observational rigor within that order.

Total station EDM accuracy is stated as ±(a mm + b ppm x D); for a 1,000 m shot at 2 mm + 2 ppm the distance uncertainty is ±4 mm before other errors.

Prism constant must be matched to the prism type (typically 0 mm for a standard round prism, -30 mm for some mini prisms); a mismatch shifts every distance by that amount.

Traverse closure ratio = total traverse length / linear error of closure; a 1:10,000 closure over 2,000 ft permits about 0.2 ft of misclosure.

RTK GNSS vertical accuracy is roughly two to three times worse than horizontal; check shots on known control and use a base-rover baseline short enough for fixed solutions.

For static GNSS sessions, longer occupation improves ambiguity resolution; log at 1 Hz or slower for baselines under a few kilometers and observe satellites above the elevation mask.

Differential leveling misclosure is checked against the allowable limit, often expressed as C x sqrt(distance in miles); balance backsight and foresight distances to cancel refraction and curvature error.

Refraction and curvature combined correction for a horizontal sight is approximately 0.0675 K^2 ft, where K is the distance in thousands of feet.

Set at least two intervisible reference points and occupy a backsight with a known azimuth; check the instrument's horizontal collimation and vertical index error before precise work.

Record field notes with instrument height, target height, weather, and time so measurements can be independently recomputed and defended.

Latitude = distance x cos(azimuth) and departure = distance x sin(azimuth); a closed traverse must sum to zero for both, and the residual is the linear error of closure.

Compass rule distributes misclosure proportional to course length; transit rule distributes it proportional to latitude and departure magnitude.

Area by coordinates (shoelace): 2A = sum of (E_i x N_(i+1) - E_(i+1) x N_i); take the absolute value and divide by two.

Coordinate geometry inverse: distance = sqrt(dE^2 + dN^2) and azimuth = atan2(dE, dN), normalized to 0-360 degrees.

Horizontal curve: T = R tan(I/2), L = R x I (radians), and the long chord = 2R sin(I/2); I is the intersection angle.

Vertical curve: at any distance x from the BVC, elevation = BVC elevation + g1 x + ((g2 - g1) / (2L)) x^2.

Least squares adjustment minimizes the sum of squared residuals weighted by observation variance; the reference variance near 1.0 indicates consistent weighting.

A map's stated scale of 1:24,000 means 1 in on the map equals 2,000 ft on the ground; a plotted position error of 0.02 in represents about 40 ft.

Compare computed areas and closure statistics against the standard for the survey purpose before accepting the plat; document residuals and any rejected observations.

The PLSS creates townships six miles square containing 36 sections of one square mile (640 acres); sections are numbered boustrophedon starting at the northeast corner.

The point of beginning of the PLSS in Indiana is the Second Principal Meridian intersection with the baseline near the Ohio River; Indiana lands were surveyed under the Act of 1802.

Correction lines and standard parallels are run every 24 miles (or as the survey instructed) to control convergence of meridians; guide meridians close on them.

Fractional lots and government lots arise where the regular section subdivision meets a boundary such as a meander line, reservation, or base line.

A meander line is not a boundary of title; it marks the water's edge for area computation, and title extends to the water per state law.

Original section corners are set by the GLO survey; lost corners are reestablished by proportionate measurement between existing accepted corners, not by simple remeasurement.

Single proportionate measurement restores a lost corner on a line between two known corners; double proportionate is used for lost interior corners with corners on all sides.

Subdivision of a section: half-sections by midpoints of lines, quarter-sections by lines between the midpoints of opposite sides; the center of the section is the intersection of quarter-section lines.

Indiana requires a land surveyor to record a monument record for corners established and to reference the recorded plat and instrument numbers in the surveyor's certification.

Indiana land surveyor licensure is administered by the Indiana Professional Licensing Agency with the Board of Registration for Land Surveyors; licensure requires education, experience, and examination.

Indiana requires continuing professional competency (continuing education) for license renewal; keep records of approved hours and report them at renewal.

A surveyor may not practice beyond competence; when a project requires expertise outside it, obtain qualified assistance and disclose the limitation.

A surveyor's seal and signature certify responsibility for the work; sealing a plan not prepared or reviewed under the licensee's direct supervision is prohibited.

Confidential client information may be disclosed only with consent or where required by law, court order, or to prevent a serious threat.

Conflicts of interest must be disclosed in writing; a surveyor may not accept compensation from more than one party for the same service without all parties' informed consent.

Retain field notes, computations, and records to support the survey; provide copies to the client and make records available as required by board rules and statute.

A surveyor must report a known error or omission in prior work to the affected client and appropriate parties, and correct it without concealment.

Ethical practice requires honest reporting of measurements and opinions; a surveyor may not alter or misrepresent evidence to support a desired boundary.