Measurement-range workbook
Show how entered dimensional uncertainty changes a rectangular plan-area estimate.
Calculation basis
Central area = length × width − excluded. Low/high bounds use both dimensions at their entered lower/upper limits, then subtract the fixed exclusion.
A simple rectangular bounding range, not a statistical confidence interval or survey. The exclusion is treated as exact. Slopes, irregular shapes, correlated errors, overlap and field access need separate measurement review.
Give the uncertainty a stated basis
Enter the central rectangular length and width, then the uncertainty either way for each dimension. The workbook combines the lower dimensions for one bound and the upper dimensions for the other. This is a simple envelope, not a statistical confidence interval or an estimate of survey accuracy.
For an illustrative 20m by 10m rectangle with length uncertainty of 1m, width uncertainty of 0.5m and a fixed 30m² exclusion, the low net bound is 150.5m², the central figure is 170m² and the high bound is 190.5m². The resulting 40m² range illustrates why the input basis matters.
Keep excluded-area uncertainty visible
The exclusion is treated as exact in this model. If the exclusion is uncertain, the shown range does not capture that uncertainty. Overlapping shapes, curved edges, slope surface measurements and correlated errors also need a different method or separate review.
Improve the measurement before fixing the quantity
A wide range may identify a useful next task: remeasure a difficult boundary, clarify an exclusion or agree the required area basis. It is not a reason to automatically buy or apply the high-bound quantity. Procurement allowances and application rates should remain separately authorized decisions.
Preserve the sketch and the limits
The handoff includes the central dimensions, uncertainty entries, fixed exclusion and all three results. Add a dated sketch and explain how the dimensions were obtained. Another reviewer should understand what the range includes and what remains unmeasured before relying on it for a scope or quantity decision.