Elements of surveying and levelling; with descriptions of the instruments and the necessary tables (1870)
Davies, Charles, 1798-1876 · New York and Chicago, A. S. Barnes & Company · leaf 219
uppose that- the horizontal planes areto be taken at distances of 6 feet. TVe may find the pointsin which the contour lines intersect the lines at right angles,as in Example Eirst. If only a rough plot is needed, theSurveyor may take the plot thus commenced, into the field,and by the eye trace the… … 30. The contour lines may be traced on the ground, aafollows: Set up the level at a, and observe that the back-sight,to the stake, placed at (^3), gave a reading of 11.432. Depressthe yane equal to the distance between the horizontal secantplanes, that is, 6 feet, which is done by placing it at the…
Surveying
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