The Elevation Factor equation EF = R/(R+H+N) implies what about distortion at high elevations?

• A. The factor approaches 1 as height increases
• B. The factor decreases as height increases
• C. The factor increases without bound as height increases
• D. The factor remains constant regardless of height

Answer: (A)

The Elevation Factor tells you how much the vertical measurement is affected by Earth's curvature and atmosphere. It’s defined as EF = R/(R + H + N), where R is a large, fixed radius and H and N are the height-related terms from curvature and refraction. Because R is very large, the denominator is only slightly bigger than R for practical heights, so the ratio stays very close to 1. In other words, even as elevation changes, the distortion remains a small fraction of the measurement, so EF effectively approaches 1 at higher elevations. This is why the best interpretation is that distortion diminishes in relative impact as elevation grows within typical surveying ranges.