Cadastral and Public Land Survey System
Domain 4 tests the PLSS as it exists in Iowa: original GLO surveys referenced to the Fifth Principal Meridian, the corner nomenclature, retracement rules for lost and obliterated corners, and the lots created by fractional sections and meander lines.
The original survey
- Townships are six miles square, numbered north from the base line and ranged east or west of the Fifth Principal Meridian; Iowa's GLO work was largely done in the 1830s–1850s.
- Sections are numbered 1–36 beginning in the northeast corner and running boustrophedon; nominal area 640 acres.
- Corners: standard (on township and section lines), closing (where a new line closes on an older one, typically the north and west township lines), quarter, meander, and witness corners.
Lost versus obliterated
- Obliterated: some physical or collateral evidence of the original position remains - restore from that evidence, not from proportion.
- Lost: nothing remains. Restore by single proportionate measurement between the nearest existent corners on the same line. Double proportion (running both latitude and departure separately) is a last resort and is de-emphasized in the 2009 Manual of Surveying Instructions.
Fractional sections
Meander lines along the Missouri and Mississippi do not bound title; the water does. Lots in fractional sections are numbered and their areas come from the official plat, not from 40-acre arithmetic.
Worked example
A lost quarter corner lies between two existent section corners measured 5,284.20 ft apart; the record distance from the south section corner is 2,640.00 ft. Single proportion: (2,640.00/5,280.00) × 5,284.20 = 0.5 × 5,284.20 = 2,642.10 ft from the south corner. The 2.10 ft goes to the north half; the corner is not set at the record distance and not at the simple midpoint of a line whose ends disagree with record.
Traps
Double-proportioning when one corner is existent; treating the computed center of section as a monument; assuming 640 or 40 acres in fractional sections; ignoring closing corners; confusing "obliterated" with "lost."