This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1907 edition. Excerpt: ...value. 129. Elevations and depressions.--Incidentally, this observation affords a method for obtaining the altitude of peaks and other prominent objects in relation to that of the occupied station which should always be taken advantage of; for while it is only occasionally that the surveyor has an ...
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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1907 edition. Excerpt: ...value. 129. Elevations and depressions.--Incidentally, this observation affords a method for obtaining the altitude of peaks and other prominent objects in relation to that of the occupied station which should always be taken advantage of; for while it is only occasionally that the surveyor has an opportunity to determine a complete system of contour lines by a leveling instrument, and such lines are of minor value to the navigator, the altitude of the more conspicuous points is an essential to a good navigating chart. The observation consists in measuring the angle of elevation (or depression) of the point whose height is required above (or below) the horizontal of the occupied station; this measurement is preferably made with a theodolite having a vertical circle, but a sextant and artificial horizon may be substituted. In figure 32, let A be the occupied point, and B, an observed point at a greater elevation; AM, the tangent at A to the refracted ray of light between A and B (the latter shown dotted): AH, the true horizontal of A, cutting the vertical line through B at a height B'H above the earth's surface; 0, the center of the earth; and D, the angle in minutes subtended by AB, equal to the horizontal distance between those points in nautical miles, as given by the results of the survey. It has been found that the effect of refraction is such that the observed angle, MAH, will, under normal atmospheric conditions, be greater than the true angle of elevation, BAH, by an amount equal to one-thirteenth of the angular distance, D. Eemembering this, and regarding BE A as a right angle, we have: BAE = MAE--TVD;. BE = D tan BAH; BB' = BE + B'H. In the first equation, D is taken in minutes of arc, these being equivalent to nautical miles; in...
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Add this copy of Elements Of Hydrographic Surveying to cart. $16.27, new condition, Sold by Ingram Customer Returns Center rated 5.0 out of 5 stars, ships from NV, USA, published 2022 by Legare Street Press.
Add this copy of Elements of Hydrographic Surveying to cart. $18.99, good condition, Sold by Robert Harper Books rated 5.0 out of 5 stars, ships from Hyattsville, MD, UNITED STATES, published by Annapolis, MD. : The United States Naval Institute.
Edition:
Annapolis, MD. : The United States Naval Institute
Add this copy of Elements of Hydrographic Surveying to cart. $20.00, good condition, Sold by Stone Soup Books rated 3.0 out of 5 stars, ships from Camden, ME, UNITED STATES, published 1908 by The United States Naval Institute.
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Good+/no DJ. 12mo, dark blue cloth binding with gilt lettering, cover is soiled, owner's name, a book on hydrographic surveying, illustrated with engravings and fold-out charts, index, 176 pages.
Add this copy of Elements Of Hydrographic Surveying to cart. $26.87, new condition, Sold by Ria Christie Books rated 5.0 out of 5 stars, ships from Uxbridge, MIDDLESEX, UNITED KINGDOM, published 2022 by Legare Street Press.
Add this copy of Elements Of Hydrographic Surveying to cart. $27.44, new condition, Sold by Ingram Customer Returns Center rated 5.0 out of 5 stars, ships from NV, USA, published 2022 by Legare Street Press.
Add this copy of Elements Of Hydrographic Surveying to cart. $40.17, new condition, Sold by Ria Christie Books rated 5.0 out of 5 stars, ships from Uxbridge, MIDDLESEX, UNITED KINGDOM, published 2022 by Legare Street Press.
