Inputs
AdvancedTip: If you omit the known closing elevation the calculator assumes a closed loop back to the starting benchmark.
Results
What is Loop Closure
Loop closure in leveling is the test that compares the computed closing elevation with the known benchmark value after a survey returns to its start point. The difference is the misclosure. Surveyors evaluate if this difference is within allowable error then distribute corrections along the route to produce adjusted elevations for reliable maps and construction control across diverse site conditions.
FAQs
How do I compute misclosure
Sum all elevation changes BS minus FS to get the net change then compare the computed closing elevation with the known closing benchmark the difference is the misclosure.
What if I do not know the closing benchmark elevation
Leave the field empty and the tool assumes a loop back to the starting benchmark so misclosure equals the net elevation change.
How is allowable misclosure calculated
It uses a coefficient in millimeters multiplied by the square root of total distance in kilometers then converts to meters.
Can I use this for open runs
Yes but you must supply a known closing elevation to evaluate the misclosure properly.
How are corrections distributed
Corrections are distributed in proportion to cumulative distance also known as distance weighting which is standard for leveling adjustments.
What if I do not enter distances
The calculator uses the total distance if provided otherwise it distributes corrections evenly by station as a practical fallback.
Which order or class should I pick
Select the specification that matches your project requirements if unsure choose Third Order as a general field standard or set a custom coefficient.
Does the tool flag pass or fail
Yes it compares the absolute misclosure to the allowable value and shows a clear pass or fail status.