Figure 10-3.—Storm sewer plan and profile.understanding of horizontal and vertical curves. Thosecross-sectional areas) and then multiply that average-will be discussed in the next chapter.Earthwork ComputationsComputing earthwork volumes is a necessaryactivity for nearly all construction projects and is oftenaccomplished as a part of route surveying, especiallyfor roads and highways. Suppose, for example, that avolume of cut must be removed between two adjacentstations along a highway route. If the area of thecross section at each station is known, you cancompute the average-end area (the average of the twoend area by the known horizontal distance between thestations to determine the volume of cut.To determine the area of a cross section easily, youcan run a planimeter around the plotted outline of thesection. Counting the squares, explained in chapter 7of this traman, is another way to determine the area ofa cross section. Three other methods are explainedbelow.AREA BY RESOLUTION.— Any regular orirregular polygon can be resolved into easilycalculable geometric figures, such as triangles and10-7