Principles and Practice of Surveying Exam (PS) Public Land Survey System (PLSS) and Federal Surveys Flashcards

24 sample cards from the Public Land Survey System (PLSS) and Federal Surveys deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. State the fundamental rule governing the order of priority of evidence in corner restoration.

   Proportionate measurement is a method of LAST resort. Only when a corner is truly lost (no monument, accessories, or acceptable evidence of original position) may proportionate measurement be applied; an obliterated corner must be re-established at its recovered original position, not proportioned.

2. What is 'single proportionate measurement,' and to what kinds of corners does it apply?

   Single proportionate measurement restores a lost corner on a straight line (controlled in one direction) by distributing the difference between record and remeasured distances proportionally between the two nearest identified original corners on that line. It applies to quarter-section corners and to corners on standard parallels/township lines controlled in only one direction.

3. Write the formula for the corrected (proportioned) distance to a lost corner using single proportionate measurement.

   $$D_{c} = D_{r}\times\frac{L_{m}}{L_{r}}$$ where $D_{c}$ is the corrected field distance to the lost corner, $D_{r}$ is the record distance to it, $L_{r}$ is the total record distance between the two controlling found corners, and $L_{m}$ is the total remeasured distance between them.

4. What is 'double proportionate measurement,' and to which corners does it apply?

   Double proportionate measurement restores a lost corner controlled in TWO directions (both latitudinally and longitudinally)—typically an interior section corner common to four sections. The position is fixed by proportioning between the nearest found corners on the north-south line AND on the east-west line, then combining the two results.

5. Outline the procedure for double proportionate measurement of a lost interior section corner.

   1) Identify nearest found original corners north, south, east, and west. 2) Apply single proportion north-south to get a latitude position. 3) Apply single proportion east-west to get a longitude position. 4) The lost corner lies at the intersection: take the N-S proportioned position for the latitude (Y) and the E-W proportioned position for the longitude (X).

6. In double proportionate measurement, which coordinate is taken from the N-S proportion and which from the E-W proportion?

   The latitude (north-south, Y) coordinate is taken from the north-south single proportion; the longitude (east-west, X) coordinate is taken from the east-west single proportion. A temporary point is set from each and the corner is placed at the intersection of a meridian through the N-S point and a latitude through the E-W point.

7. What is the 'index correction' (single proportion adjustment) and how does a proportion factor express it?

   The index correction is the ratio applied to record distances to reconcile them with modern remeasured distances. The proportion (index) factor is $k=\dfrac{L_{m}}{L_{r}}$ (measured total ÷ record total); each record distance is multiplied by $k$ to distribute the total discrepancy uniformly.

8. What is the 'grant boundary' or 'broken boundary' method, and when is it used?

   It is a proportionate method used to restore lost corners along an irregular (broken) line—such as a private land grant boundary or a non-rectangular line. Record courses and distances are scaled by the ratio of total measured to total record length along the traverse, distributing error along the broken line proportionally.

9. Define 'corner perpetuation' and name a typical legal instrument used to accomplish it.

   Corner perpetuation is the permanent preservation of a corner's position so it can be recovered in the future, accomplished by setting durable monuments, recording reference (accessory) ties, and filing a Corner Record (or Record of Survey) with the county/state per perpetuation statutes.

10. What is a 'reference monument' (accessory), and why is it set?

    A reference monument is an accessory marker set a known bearing and distance away from the true corner when the corner itself falls in a location where a monument cannot be maintained (e.g., in pavement, a stream, or on rock). It allows the true corner position to be recovered by measurement from the reference.

11. List the principal types of corner 'accessories' recorded in original surveys.

    Bearing trees (witness trees), bearing objects (e.g., notable rocks), mounds of stone, pits, memorials buried beneath the monument, and reference monuments. These collateral marks help re-identify and perpetuate the corner position.

12. What is a 'bearing tree' (witness tree), and what data are recorded for it?

    A bearing tree is a living tree near a corner, blazed and scribed by the original surveyor. Recorded data include the species, diameter, and the bearing and distance from the corner to the tree, enabling recovery of the corner if the monument is lost.

13. How were 'mounds and pits' used by original surveyors to mark corners in treeless areas?

    In prairie or treeless terrain lacking bearing trees, surveyors raised a mound of earth or stone over the corner and dug pits in a prescribed pattern (e.g., a specified number of pits at set distances and directions) so the disturbed ground served as recoverable evidence of the corner.

14. What are 'original field notes' and the 'official plat,' and what is their legal standing?

    Field notes are the surveyor's written record of measurements, monuments, accessories, and topographic calls; the plat is the official map drawn from them. Once approved by the BLM (formerly GLO), they are the legal record—the boundaries they create are unchangeable and control over later measurements.

15. State the foundational legal principle regarding original monuments versus later measurements.

    Original monuments, when found undisturbed, control over record bearings and distances. The location of a boundary is where the original surveyor set it, even if later, more accurate measurements show different dimensions—'the corner is where the surveyor set it.'

16. When reconciling record measurements with modern surveys, what is the proper treatment of a discrepancy in distance between two found original corners?

    The found original corners control; the discrepancy between record and measured distance is distributed proportionally among the intervening (lost or interior) points by proportionate measurement. The found corners are NOT moved to fit the record.

17. What is the difference between a 'dependent resurvey' and an 'independent resurvey'?

    A dependent resurvey retraces and re-establishes the lines of the ORIGINAL survey, restoring lost/obliterated corners to their original positions and preserving existing property rights. An independent resurvey establishes NEW lines and corners for unpatented public land, used when the original survey is so defective that retracement is impractical, while protecting bona fide rights of patented lands.

18. Which type of resurvey preserves the original boundary positions and existing landowner rights, and why is it preferred?

    The dependent resurvey. It is preferred because it honors the legal principle that original boundaries are fixed; it merely recovers and re-monuments the original corners without altering vested property rights.

19. Under what condition may the BLM conduct an independent resurvey rather than a dependent resurvey?

    When the original survey is so grossly erroneous, fraudulent, or fragmentary that the original corners and lines cannot be reliably retraced, AND when doing so will not impair bona fide property rights of existing patentees (which are protected and segregated).

20. What is the legal distinction between 'navigable' and 'non-navigable' waters in the PLSS regarding land ownership?

    Beds of navigable waters were retained by the states (held in trust for the public), so federal patents extend only to the ordinary high-water mark and lands were meandered. Beds of non-navigable waters generally passed to the riparian patentee. Navigability is determined as of the date of statehood.

21. What is 'convergence,' and approximately how is the linear convergence of two meridians 6 miles apart related to latitude?

    Convergence is the angular/linear coming-together of meridians toward the pole. The linear convergence $c$ over a north-south length is approximately $$c \approx d\,\Delta\phi\,\tan(\text{lat})$$ in concept; for two meridians, convergence increases with latitude (proportional to $\tan$ of the latitude), causing the north side of a township to be shorter than the south side.

22. Distinguish a 'retracement survey' from a 'resurvey' in BLM terminology.

    A retracement (often a dependent resurvey component) follows the footsteps of the original surveyor to recover and re-mark the original lines without creating new ones. A resurvey (dependent or independent) is an official re-running that may also re-establish lost corners (dependent) or create new boundaries (independent).

23. What is a 'witness corner,' and how does it differ from a true corner and a reference monument?

    A witness corner is a monument set ON the survey line, a measured bearing and distance from the true corner, when the true corner position is inaccessible (e.g., in water). It differs from a reference monument (which need not be on line) and from the true corner, whose position it merely witnesses.

24. Summarize the BLM-prescribed priority (hierarchy) of evidence for locating a boundary corner.

    In order: (1) natural monuments/boundaries called for; (2) original artificial monuments and their accessories; (3) record courses and distances from the original survey; (4) testimony and collateral evidence of the original position; and only when the corner is truly lost, (5) proportionate measurement from the nearest existent interdependent corners.

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