Presampling - Field Sampling: Principles and Practices in Environmental Analysis - page 60

FIGURE 3.4 A contour map of fields 12a, 12b, and 12c showing contour lines
which give the elevation of different parts of the field.
FIGURE 3.5 An example of a portion of a DOQQ map from Clinton County,
Ohio, showing roads, buildings, and fields.
GIS systems An example of a portion of a DOQQ map is shown in Figure 3.5 [3, 4].
The DOQQ images produced have both the look of a photograph and the geometric
qualities of a map. They are a true representation of the Earth's surface. Because of this