b. Latitude and Longitude. Latitude and longitude is the position of any point in relation to
where the north-south (NS) line (the zero or Greenwich meridian) intersects the east-west (EW) line (the
zero parallel or the earth's equator). This location method is known as the geodetic-coordinates method.
c. Distance and Direction. Another location method is distance and direction. In the following
examples, the location is given in terms of the point's direction and the distance from the reference
point:
Example 1: A certain point is located 15 miles southwest of the center of Minneapolis.
Example 2: In Figure 1-2, standing at the corner of the garage, the tree is 45 clockwise
from the edge of the driveway and 50 steps away from the garage.
Figure 1-1. Coordinates of a point on a grid
1-5. Plane Surveying. The branch of surveying in which the mean surface of the earth is considered a
plane surface is generally referred to as plane surveying. In plane surveying, the earth's curvature is
neglected, and computations are made using the formulas of plane geometry and trigonometry. In
general, plane surveying is applied to surveys of land areas and boundaries (land surveying) where the
areas are of limited extent. Plane surveying is also used when the required accuracy is so low that
corrections for the effect of curvature would be negligible as compared to the errors of observations.
For small areas, precise results may be obtained with plane-surveying methods, but the accuracy and
precision of such results will decrease as the area surveyed increases in size. Generally, plane
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