Suppose that you are standing at station
0 + 00, figure 14-16. The elevation of this station
is 122.53 ft. Your HI is therefore
.122.53 + 5.5 = 128.03 ft.
You round off cross-section elevations to the
nearest 0.1 ft. If a rodman holds a rod 40 ft to
the left of the center line at station 0 + 00 and
you read 1.9 ft on the rod, then the elevation of
the point plumbed by the rod is
128.0 – 1.9 = 126.1 ft.
The rodman now moves on to a point 30 ft
from the center line. If you read 3.3 ft on the rod,
the elevation of this point is
128.0 – 3.3 = 124.7 ft.
Going on in this manner, you determine the
elevations at all the required points on the cross
section. You then move to the next station and
repeat the process.
Cross section notes are recorded in the field
book by using one of two basic methods. In the
first, and often preferred, method, begin at the
bottom of the page and read upward, as shown
in figure 14-20. This method helps to keep you
oriented in the direction in which the line runs and
helps to prevent confusion as to which is the right
or left side of the line. It therefore reduces the
possibility of recording your readings on the
wrong side of the center line.
In the second method, the notes are recorded
in the conventional manner of reading from top
to bottom of the page. Whichever method you
use, you must remember that as you stand
facing the direction in which the line runs, left
Figure 14-20.-Sample field notes from cross-section leveling at first three stations shown in figure 14-7.
14-19
