NCEES Principles and Practice of Surveying Practice Exam

According to National Map Accuracy Standards, what percentage of field check elevation should fall within one-half the contour interval?

1. 80%

2. 90%

3. 95%

4. 100%

The correct answer is: 90%

According to the National Map Accuracy Standards, the standard specifies that 90% of field-checked elevation points should fall within one-half the contour interval. This requirement ensures that the topographical representation of the land is sufficiently accurate for various applications, such as engineering, planning, and resource management. In practical terms, if a map has a contour interval of 20 feet, this means that 90% of the points surveyed must have their actual elevations fall within 10 feet of the contour lines represented on the map. Meeting this standard is crucial for maintaining the reliability of the data, as it provides users confidence in the elevation information. This adherence to the established accuracy threshold allows surveyors and engineers to make informed decisions based on the map's representation of the terrain. Understanding this standard helps professionals in the surveying field to ensure high-quality mapping and elevation data, which is critical for effective project planning and execution.