Stuart, Edwin Roy, 1874- · New York, McGraw-Hill · leaf 82
ations shown onthe contours on the map. So long as the elevations along theline of sight are greater than the elevations of the contours ofthe ground, the ground is invisible. When a point is reachedwhere the opposite is true, the ground becomes visible. Thepoint where the line of sight strikes the… … Fig. 26.—Line of Screen on Spur. In determining the line of screen on a spur, it may only benecessary to draw from the observation point lines tangent tothe contours of the spur, and then connect the points of tan-gency, as in Fig. 26. To permit the use of this method, the ob-servation point must…
Military sketching · Maps, Military
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