Surveying
Traverse Precision Ratio (Relative Precision)
Summary
The precision ratio of a traverse is its total length divided by its linear misclosure, written as 1:N. A loop of 2406.58 m that misses closure by 0.100 m has a precision of 1:24,100. Larger N means better closure. The value is checked against the project specification before any adjustment is applied.
Definition
Relative precision: the ratio of linear misclosure to total traverse length, expressed as 1:(ΣL / misclosure).
- Precision = 1 : ΣL / e
- e = √(fE² + fN²)
- Compute before adjustment
- Typical targets 1:5,000 to 1:50,000
Formula
Use horizontal (and, on a grid, scale-corrected) distances in ΣL.
Typical specifications
| Application | Typical minimum |
|---|---|
| Reconnaissance, low-order mapping | 1:3,000 – 1:5,000 |
| Property boundaries, engineering | 1:10,000 |
| Construction control | 1:10,000 – 1:20,000 |
| Higher-order control (classical third order) | 1:10,000 – 1:20,000 |
| Second and first order control | 1:50,000 – 1:100,000 |
Limitations
Precision ratio only reflects internal consistency. A closed loop can show excellent closure while carrying a scale error or a wrong orientation from the starting control. Link traverses between independent control, or GNSS checks, catch these systematic errors.
Worked example
The traverse meets a 1:10,000 or 1:20,000 specification but not 1:50,000.
FAQ
Is 1:20,000 better than 1:10,000?
Yes. 1:20,000 means one unit of misclosure per 20,000 units travelled, which is half the relative error of 1:10,000.
Should precision be computed before or after adjustment?
Before. After adjustment the traverse closes exactly by construction, so the ratio would be meaningless.
Does precision ratio prove the coordinates are correct?
No. It shows the observations agree with each other and with the closing control, but systematic errors in control, scale or orientation can remain.
Related tools and articles
Tools
Articles
- Traverse Adjustment: Complete Guide for SurveyorsA traverse adjustment turns measured angles and distances between control points into a consistent set of coor…
- Bowditch Rule (Compass Rule) Traverse AdjustmentThe Bowditch rule, also called the compass rule, adjusts a closed or link traverse by distributing the misclos…
- Coordinate ClosureReference topic
- Closed Traverse: Loop and Link Traverses ExplainedA closed traverse provides an independent check on its own observations. A loop traverse returns to its starti…
References
- Ghilani, C. D. & Wolf, P. R. Elementary Surveying: An Introduction to Geomatics, 15th ed., Pearson, 2018 (traverse computations and adjustments).
- Federal Geodetic Control Committee. Standards and Specifications for Geodetic Control Networks, 1984 (traverse order and class closure standards).
Cite this page
GeoCAD Bridge. “Traverse Precision Ratio (Relative Precision).” GeoCAD Bridge Knowledge Center, updated 2026-10-05. https://www.geocadbridge.com/knowledge/survey-precision-ratio/