The allowable error of closure for third order leveling

• A. 0.5 mm per km
• B. 0.1%
• C. None
• D. 2 mm per km

Answer: (C)

In leveling, accuracy is controlled by the order of the work, and tighter orders have defined tolerances for how much misclosure is allowed. For third-order leveling, there isn’t a single fixed numeric allowance (like a specific mm per km or a percentage) that applies universally. Instead, the quality is assessed through the statistical consistency of the measurements—looking at the overall residuals and standard deviations—rather than a strict per-kilometer closure rule. That’s why there isn’t a standard numeric misclosure value to memorize for third order, making “None” the appropriate choice.