3. Make sure that, in computing latitudes and
departures, you have not accidently used cosine instead
of sine or vice versa. The latitude of a traverse line
equals the product of the length times the cosine of the
bearing; the departure equals the product of the length
times the sine of the bearing.
4. Make sure that you have given each bearing the
proper compass direction; that is, the direction of the
front bearing, NOT that of the back bearing.
5. Make sure that you copied all bearings and
distances correctly.
6. Make sure that you copied all cosines and sines
correctly.
7. Make sure that you made no arithmetical errors.
If none of these procedures serves to identify the
mistake, you will have to rerun the traverse. If you must
of closure on the plot. Often, the traverse line that
contains the mistake is parallel to this line. If there is a
line that is parallel, you should start your rerun with this
one.
QUESTIONS
Q1. What are the two principal methods of indirect
leveling?
Q2. Refering to figure 7-43, you have determined
the slope distance from BM31 to point A to be
404.163 meters. If you disregard corrections for
standard error, temperature, and sag, what is
(a) the horizontal distance from BM31 to point
A and(b) the elevation at point A?
Q3. Refer to figure 7-44. What is the error of closure?
Is this error of closure satisfactory for
do this, examine the direction of the line of linear error
third-order leveling?
Figure 7-43.—Trigonometric leveling scenario for question Q2.
Figure 7-44.—Field notes for a differential-level circuit.
7-29
