The theory and practice of surveying. Designed for the use of surveyors and engineers generally, but especially for the use of students in engineering (1886)
Johnson, J. B. (John Butler), 1850-1902 · New York, J. Wiley & sons · leaf 653
ob-tained from astronomical observations. It is desirable to find the length of the line nl, of the normal 7tm, andof the radius of curvature ^V, all in terms of <?, L, and a. Also to findthe geocentric latitude in terms of a, b, and L, To find nl, we have nl^^ nd + df= yf + y—,. For the… … (3) Fig. 153, Squaring, remembering thatjK = ;^/sin L, we have, after reducing, n/ = (I - e^ sin2 L)i (A) To find the length of the normal nm = N, we have nm . nl .. x \ dl. But whence dy _b^dx a^ dl = nd tan dnl = y--j-= —x ■= {1 — e^)x \ nm = N= - nl i-e\ ii—e^sm^L)f (4)(B) 1^ APPENDIX D. 613 To…
Surveying
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