IA Land Surveyor cheat sheet

Priority of evidence in boundary retracement: natural monuments, then artificial monuments, then courses and distances, then area; written calls generally control over area computations.

Adverse possession in Iowa requires 10 years of actual, open, exclusive, hostile, and continuous possession; payment of taxes is not a statutory element for privately held land but is evidence of claim of right.

A boundary by acquiescence in Iowa requires a mutually recognized line for at least 10 years, with the adjoining owners treating the line as the true boundary.

Ambiguity in a deed is construed against the grantor (contra proferentem); a call to a monument controls over a call to a distance when they conflict.

Easements by prescription require 10 years of adverse use in Iowa; use must be open, notorious, continuous, and under a claim of right.

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

Unwritten rights such as practical location and acquiescence can establish a boundary line that differs from the deed record, so field evidence of long-standing possession must be documented.

Iowa boundary surveys should reference the recorded deed, adjoining deeds, and any prior survey plats; the surveyor reports facts and does not adjudicate title.

NAD83 (2011) and NAVD88 are the current horizontal and vertical datums in Iowa; many legacy surveys reference NAD27 or NGVD29 and require transformation.

State Plane Coordinate System in Iowa uses two zones: Iowa North (FIPS 1401) and Iowa South (FIPS 1402), both Lambert Conformal Conic projections.

Grid scale factor multiplied by elevation factor gives the combined factor; ground distance equals grid distance divided by the combined factor.

Elevation factor = R / (R + H), where R is the mean Earth radius at the latitude and H is the ellipsoidal height (approximately the orthometric height).

Iowa's real-time GNSS network (IaRTN) provides RTK corrections; check residual accuracy and repeat observations before accepting coordinates.

Geoid modeling (GEOID18) converts ellipsoidal heights from GNSS to NAVD88 orthometric heights: H = h - N.

Traverse closure: linear misclosure divided by total traverse length gives relative precision; Iowa standards for control traverses typically require 1:10,000 or better for boundary work.

Static GNSS observation sessions should be tied to at least two published control points (CORS or NGS) for datum verification.

Latitude = distance × cos(bearing); departure = distance × sin(bearing). Sum of latitudes and departures around a closed traverse equals zero.

For a closed traverse, linear misclosure = sqrt((Σlatitude)² + (Σdeparture)²); relative precision = linear misclosure / perimeter.

Compass rule (Bowditch) distributes errors proportionally to course length; transit rule distributes proportionally to latitude/departure magnitude.

Area by coordinate method (shoelace): 2A = Σ(Xi × Yi+1 - Xi+1 × Yi); double meridian distance (DMD) method also yields area from adjusted latitudes and departures.

Curve formulas: T = R tan(Δ/2); L = RΔ (Δ in radians); LC = 2R sin(Δ/2); M = R(1 - cos(Δ/2)); E = R(sec(Δ/2) - 1).

Degree of curve: arc definition D = 5729.578/R; chord definition D = 2 arcsin(50/R). Iowa DOT uses arc definition for highway curves.

Horizontal angles measured by repetition reduce random error; total station angles should be checked against a closing horizon.

Level loop misclosure is distributed by proportional distance; allowable misclosure rules of thumb are often 0.05 ft × sqrt(miles) for third-order work.

PLSS townships are 6 miles square containing 36 sections of 1 square mile each, numbered starting at the northeast corner and proceeding boustrophedon to 36 in the southeast corner.

Iowa is governed by the original public land surveys of the 5th Principal Meridian; the Iowa-Missouri boundary is the baseline for much of the state.

Section subdivision: halves to quarters; aliquot parts such as the NE1/4 of the SW1/4 identify a 40-acre tract; further subdivision uses government lots and fractional lots.

Meander corners are set at the intersection of survey lines with the banks of navigable waters; meander lines are not boundary lines.

Lost corners are reestablished by single or double proportionate measurement from accepted original corners, not by simple remeasurement of record distances.

Section corners are typically set at half-mile intervals; quarter corners are set on line between section corners by proportionate measurement.

Iowa Code Chapter 354 governs platting of subdivisions and Chapter 355 governs land surveying; both affect cadastral records.

GLO field notes and plats are the primary evidence for original corner positions; a surveyor must research the original GLO record before retracement.

Subdivision plats typically show lot lines, bearings and distances, curve data (R, L, Δ, T, LC), lot areas, and monument locations.

Iowa Code Chapter 354 requires plat approval by the governing body before recording; a plat must be filed with the county recorder.

Floodplain regulation under Iowa Code Chapter 455B and local ordinances restricts lots with base flood elevations; NFHL maps are the reference.

Minimum lot size and frontage requirements are set by local zoning; check the zoning classification before designing lot layouts.

Right-of-way dedication and street design must meet local subdivision ordinances; cul-de-sac length and radius are typically regulated.

Curve tables on plats must be internally consistent: chord and arc lengths derived from the same radius and central angle.

Monumentation of subdivision corners is required; Iowa rules require setting durable monuments at lot corners and referencing them to the plat.

Digital mapping: coordinate geometry (COGO) checks should reconcile plat areas against deed areas before recording.

Construction staking transfers design positions to the field using control points; check shots on known monuments verify setup accuracy.

Slope staking for grade: cut/fill = design elevation - existing elevation; horizontal offset from centerline derived from side slope ratio.

Grade stakes show cut or fill to finished grade; a cut stake indicates the design grade is below existing ground.

As-built surveys document constructed improvements; compare measured positions to design and report deviations.

Machine control and GPS grading require a verified site calibration and local coordinate transformation to the project datum.

Horizontal and vertical alignment data for highways come from the Iowa DOT plans; curve and spiral data must be checked against plan sheets.

Quantity computations: average end area method and prismoidal formula; volume = L × (A1 + A2)/2 for average end area.

Safety and traffic control on construction sites follow MUTCD and Iowa DOT work zone requirements; survey crews must coordinate with contractors.

Iowa land surveying is regulated by the Iowa Engineering and Land Surveying Examining Board under Iowa Code Chapter 542B.

A professional land surveyor license requires education, experience, and passage of the NCEES PS exam plus the Iowa-specific jurisprudence exam.

Iowa requires continuing education for license renewal; verify current hour requirements with the board before renewal.

Surveyors must seal and sign plats and reports; offering to perform surveying without a license is prohibited.

Ethical practice: disclose conflicts of interest, maintain confidentiality of client information, and avoid misrepresentation of qualifications.

Iowa Code Chapter 355 addresses land surveying practice, including monumentation and record-keeping requirements.

Records of surveys and field notes should be retained per board rules; a surveyor may be required to provide copies to the client or successor.

Written contracts should define scope, deliverables, fees, and limitations; professional liability insurance is common but not a substitute for competence.