Which of the following is NOT a method used in the reduction of distances from the ground to grid?

Using land survey maps is not a method for reducing distances from the ground to grid. The reduction of distances typically involves more technical processes that account for the curvature of the earth and the differences between a geoid and the ellipsoid model of the earth's shape.

Elevation above the ellipsoid provides a reference point for determining real-world distances, while calculating the scale factor adjusts measurements based on the specific conditions of the survey area. Applying geoidal separation accounts for variations between the geoid (the mean sea level surface) and the ellipsoid, which is essential for precise geodetic calculations. In contrast, land survey maps represent existing data and information about land features, but they are not a methodology for the direct reduction of distances in the same sense.