PLSS Manual Flashcards
PublicFlashcards covering Public Land Survey System concepts from the BLM Manual of Surveying Instructions 2009
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Cards (52)
What is the area of one acre in square chains?
10 square chains
What is the Public Land Survey System (PLSS)?
The rectangular surveying system used in the United States to survey and describe public domain lands, established by the Land Ordinance of 1785.
What are the three California principal meridians?
Mount Diablo Meridian (1851), San Bernardino Meridian (1852), and Humboldt Meridian (1853)
What is the area of a standard township?
36 square miles (nominally 6 miles × 6 miles)
How many sections are in a standard township?
36 sections
What is the area of a standard section?
640 acres (nominally 1 mile × 1 mile)
How many chains are in one mile?
80 chains
How many links are in one chain?
100 links
How many feet are in one chain?
66 feet (U.S. Survey Foot)
What is the difference between U.S. Survey Foot and International Foot?
Approximately 2 parts per million; U.S. Survey Foot: 1 meter = 39.37 inches (exact); International Foot: 1 inch = 25.4 mm (exact)
What section number is in the northeast corner of a township?
Section 1
What section number is in the southeast corner of a township?
Section 36
In what direction does section numbering proceed from Section 1?
West to Section 6, then east to Section 12, alternating west and east (serpentine pattern)
Which sections typically contain fractional lots?
Sections along the north and west boundaries of the township (Sections 1-6, 7, 18, 19, 30, 31)
What is a corner in PLSS terminology?
A point on the earth's surface, determined by the surveying process, that defines an extremity on a boundary of the public lands or any subdivision thereof
What is an existent corner?
A corner whose position can be identified from physical evidence of the original monument
What is an obliterated corner?
A corner where no physical evidence of the original monument remains, but position can be determined from other evidence
What is a lost corner?
A corner whose position cannot be determined from any reliable evidence and must be restored by record and proportionate measurement
What is a witness corner?
A monumented point near a corner, established when it is impracticable to occupy the corner site
What is a reference monument?
An accessory monument established where the corner site cannot support a permanent monument or where the monument would be liable to destruction
What is single proportion?
Method of restoring lost quarter-section corners by proportioning record distances along a single line between two identified corners
What is double proportion?
Method of restoring lost corners (typically section corners) by proportioning in both N-S and E-W directions from four identified corners
What corners control restoration of a lost section corner?
Four section corners: two on the N-S line (north and south) and two on the E-W line (east and west)
What is the fundamental principle for restoring lost corners?
Lost corners must be reestablished in the identical positions they originally occupied, using record and proportionate measurement
What is the ordinary high water mark (OHWM)?
The line below which water impresses on the soil, depriving it of terrestrial vegetation and agricultural value
What is the boundary for tidal waters?
The line of mean high tide (MHT), averaged over 18.6 years
What is a meander line?
A traverse approximating the margin of a permanent natural body of water, run for calculating acreage and platting purposes—NOT a boundary
What is a meander corner?
A corner established at the intersection of a survey line with the ordinary high water mark of a meanderable body of water
What minimum width requires meandering for nonnavigable rivers?
3 chains average right-angle width
What minimum area requires meandering for nonnavigable lakes?
50 acres
What is the maximum allowable alignment deviation for township exteriors?
14 minutes from cardinal for new boundaries; 21 minutes for previously established boundaries
What is the limit of closure for township exteriors?
1/4000 of perimeter in latitude OR departure
What is the maximum measurement deviation for rectangular limits?
25 links in 40 chains
What is convergency in PLSS surveys?
The approaching of meridians toward each other as they extend northward, requiring adjustments in township surveys
In what direction are meridional section lines surveyed?
From south to north, parallel to the east boundary of the township
Where is excess/deficiency in measurement placed in a regular township?
In the north and west half-miles of sections along the township boundaries
What is a sectional guide meridian?
A correction line surveyed when the east boundary of a township is defective, leaving the north boundary defective in position
What is a sectional correction line?
A correction line surveyed when the south boundary of a township is defective, leaving the west boundary defective in position
How is the center of a section established?
By the intersection of straight lines connecting opposite quarter-section corners
Where are interior sixteenth-section corners placed on a regular section?
At midpoints between quarter-section corners and section corners, and between quarter-section corners and section center
What controls subdivision of fractional sections when no opposite QC exists?
Lines run due N-S or E-W (or on mean bearing) from established corners to the boundary
What is the fundamental principle regarding original corners?
Original corners shall stand as the true corners they were intended to represent, even though not exactly where professional care might have placed them
What is the penalty for destroying survey monuments (18 U.S.C. 1858)?
Fine or imprisonment not more than six months, or both
What is a dependent resurvey?
A retracement and restoration of the original survey without changing boundaries or creating new corners
What is an independent resurvey?
A new survey that disregards the original and creates new boundaries; requires Congressional authorization
What is the diameter of a BLM regulation post cap?
3¼ inches
How deep should a regulation post be set?
Three-fourths its length (approximately 21 inches for a 28-inch post)
What does 'SC' marked on a corner monument indicate?
Standard corner (on a base line or standard parallel)
What does 'CC' marked on a corner monument indicate?
Closing corner
From which direction are monument markings read?
From the south side of the monument
What California code recognizes U.S. surveys?
California Code of Civil Procedure § 1971 and Government Code § 8764
What is required when reestablishing lost corners in California?
Filing a Record of Survey per Business & Professions Code § 8762