Traverse Precision Ratio

Also known as closure precision · 1 in 5000

N = \frac{P}{E_c}

Worked example: 1:5000 with a 9 cm misclosure → 450 m perimeter — press Try an example to run it live, then adjust anything.

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UniversityApplied Field Engineering

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Traverse Precision Ratio explained

An error of a third of a foot means nothing until you know how far you walked to accumulate it. The precision ratio fixes that by dividing the perimeter by the misclosure and quoting the result as 1:N — one part in six thousand, say. Typical standards run 1:5,000 for ordinary boundary work, 1:10,000 for urban surveys and control, and 1:100,000 or better for geodetic networks; rough topographic traverses may be accepted at 1:3,000. The convention long predates electronic distance measurement: with Gunter's chain, which came in 66 ft lengths of a hundred links, a good chainman was expected to hold about 1:5,000 over open ground.

A worked example: a traverse with a perimeter of 2,400 ft closes with a 0.40 ft error, so N = 2,400/0.40 = 6,000 and the survey is reported as 1:6,000 — acceptable for a rural boundary, marginal for a subdivision. Two traps: the ratio always reduces to a numerator of one, so 2:12,000 is not a thing, and a suspiciously good ratio is worth investigating rather than celebrating, since it often means an angle was computed rather than measured.

Traverse Precision Ratio formula

N = \frac{P}{E_c}

Where

$N$ = Precision denominator (1 in N)
$P$ = Total traverse perimeter (m)
$E_c$ = Linear closure error (m)

Missing one of these? Work it out first, then come back

Precision denominator (1 in N) — Logarithm of a Quotient
Total traverse perimeter — Square Perimeter, Rectangle Perimeter
Linear closure error — Traverse Closure Error

Part of this formula set

Survey traverse closure

6 formulasClosing a traverse: latitudes and departures per leg, the misclosure they expose, and the precision ratio that decides whether it passes.