misclose
The discrepancy between the starting point the endpoint of the shape reconstructed from the measured dimensions and bearings of a boundary.
misclose: when your survey loop doesn't actually close
A misclose is the gap that appears when you traverse around a boundary and your measurements do not bring you back exactly to your starting point. In practical terms, if you measure the sides and angles of a property perimeter and plot those measurements, the endpoint will not coincide with the beginning. The distance between where you end up and where you started is the linear misclose; the angular misclose is the difference between your final bearing and your initial bearing when you should be parallel.
Every field measurement contains error. Compass bearings may drift, tape lengths may stretch or sag under their own weight, angles measured with a theodolite or transit contain instrumental and reading errors, and the surveyor's step length compounds cumulative distance errors. A misclose of 1 in 5000 is generally acceptable for boundary work; 1 in 10000 is considered good. This ratio compares the linear misclose to the total perimeter distance traversed. A 2 mile boundary with a 5 foot misclose would be 1 in 2112, well within tolerance for many purposes.
When misclose exceeds acceptable limits, the surveyor must return to the field and remeasure critical sections, looking for transcription errors, compass anomalies, or tape calibration drift. Sometimes a single bad angle or distance jumps out once the misclose is quantified. Once the surveyor is satisfied that measurements are sound, they distribute the misclose across the traverse using adjustment methods such as the Bowditch rule or transit rule, proportionally correcting each leg of the boundary so that the final coordinates close properly.
Misclose becomes legally and financially significant in boundary disputes, subdivision layouts, and mortgage conveyancing. A survey with unreconciled misclose is unreliable and unmarketable. Title insurance companies and lenders will reject or require remediation. Modern GPS-based surveys can achieve much tighter closure when the satellite geometry is strong, though local disturbances and multipath error still produce real-world misclose that must be accounted for.