What horizontal accuracy standard must at least 90% of points on a map match to pass NMAS?

The National Map Accuracy Standards (NMAS) were established to ensure that the accuracy of maps meets certain criteria, especially when it comes to representing the real-world features they depict. According to the NMAS, for a map to be considered accurate, at least 90% of the points must match the corresponding ground locations within a specified accuracy threshold. The horizontal accuracy standard for NMAS requires this level of accuracy for different map scales, particularly focusing on the precision needed for smaller and larger scales, such as 1:20,000.

The choice indicating that 90% accuracy is required for both smaller and larger scales than 1:20,000 highlights the essence of ensuring quality mapping across various scales. The significance here is that while the scale may change, the expectation for precision remains constant. This emphasizes the importance of maintaining high standards of accuracy regardless of the scale at which the map is produced, as it reflects on the map's reliability and usability in real-world applications.

In contrast, the other options represent specific scale ratios (1/20,000, 1/30,000, and 1/50,000), which indicate accuracy thresholds but do not capture the overarching requirement for maintaining 90% accuracy across different scales, as articulated