3. Make sure that, in computing latitudes anddepartures, you have not accidently used cosine insteadof sine or vice versa. The latitude of a traverse lineequals the product of the length times the cosine of thebearing; the departure equals the product of the lengthtimes the sine of the bearing.4. Make sure that you have given each bearing theproper compass direction; that is, the direction of thefront bearing, NOT that of the back bearing.5. Make sure that you copied all bearings anddistances correctly.6. Make sure that you copied all cosines and sinescorrectly.7. Make sure that you made no arithmetical errors.If none of these procedures serves to identify themistake, you will have to rerun the traverse. If you mustof closure on the plot. Often, the traverse line thatcontains the mistake is parallel to this line. If there is aline that is parallel, you should start your rerun with thisone.QUESTIONSQ1. What are the two principal methods of indirectleveling?Q2. Refering to figure 7-43, you have determinedthe slope distance from BM31 to point A to be404.163 meters. If you disregard corrections forstandard error, temperature, and sag, what is(a) the horizontal distance from BM31 to pointA 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 fordo this, examine the direction of the line of linear errorthird-order leveling?Figure 7-43.—Trigonometric leveling scenario for question Q2.Figure 7-44.—Field notes for a differential-level circuit.7-29
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