Surveying
Open Traverse: Uses, Risks and Checks
Summary
An open traverse starts on known control but ends on a point of unknown position, so it provides no misclosure and cannot be adjusted. It is only acceptable for short, low-risk work such as mine or tunnel advances, and even then should be checked by repeated measurement, GNSS ties or a return traverse.
Definition
Open traverse: a traverse that does not close on a point of known position, so its accuracy cannot be computed from its own observations.
- No closure check
- Cannot be adjusted
- Errors accumulate
- Add independent checks
Why open traverses are risky
Every angular error rotates all subsequent legs and every distance error shifts all subsequent points. Without closing control, a blunder such as a mis-booked angle is invisible.
How to add checks
- Measure every angle and distance twice, on both faces and in both directions.
- Observe a GNSS position or azimuth at the far end.
- Return to the start by a different route to form a loop.
- Tie to any existing control met along the way.
How GeoCAD Bridge handles open traverses
The Traverse Adjustment tool computes coordinates for open traverses but reports them as unadjusted, with no closure or precision, and warns that no independent check exists.
FAQ
Is an open traverse ever acceptable?
Yes, for short lines where closure is impossible, such as tunnels or underground mines, provided redundant measurements and later checks are made.
Can I compute a precision ratio for an open traverse?
No. Precision ratio needs a known closing point.
Related tools and articles
Tools
Articles
- Closed Traverse: Loop and Link Traverses ExplainedA closed traverse provides an independent check on its own observations. A loop traverse returns to its starti…
- Link Traverse (Connecting Traverse)A link traverse starts from known control with a known backsight and ends on different known control with a kn…
- Traverse Adjustment: Complete Guide for SurveyorsA traverse adjustment turns measured angles and distances between control points into a consistent set of coor…
References
- Ghilani, C. D. & Wolf, P. R. Elementary Surveying: An Introduction to Geomatics, 15th ed., Pearson, 2018 (traverse computations and adjustments).
- Uren, J. & Price, W. F. Surveying for Engineers, 5th ed., Palgrave Macmillan, 2010.
Cite this page
GeoCAD Bridge. “Open Traverse: Uses, Risks and Checks.” GeoCAD Bridge Knowledge Center, updated 2026-10-05. https://www.geocadbridge.com/knowledge/survey-open-traverse/