Topographic surveying; including geographic, exploratory, and military mapping, with hints on camping, emergency surgery, and photography . latitude and azimuth; a sextant for astronomic obser-vations and the measurement of horizontal and vertical angles(Art, 336); a light plane-table with sight alidade (Arts. 56and 62), to supersede the transit in rougher surveys whennecessary, and a prismatic compass (Art. 91) to replace eitherof the above. Distances may be measured by means of thestadia hairs in the transit, a light pole being marked withbands of white cloth or string or other device as a s
Topographic surveying; including geographic, exploratory, and military mapping, with hints on camping, emergency surgery, and photography . latitude and azimuth; a sextant for astronomic obser-vations and the measurement of horizontal and vertical angles(Art, 336); a light plane-table with sight alidade (Arts. 56and 62), to supersede the transit in rougher surveys whennecessary, and a prismatic compass (Art. 91) to replace eitherof the above. Distances may be measured by means of thestadia hairs in the transit, a light pole being marked withbands of white cloth or string or other device as a stadia-rod(Arts. loi and 112). Distances will be obtained in additionby triangulation (Chap. IX) or pacing, or by means of thelinen tape, or by time estimate on land or in floating downstreams (Arts. 65, 97, and 96). Two examples of exploratory surveys are illustrated inFigs. 23, 24, and 25. The first is that of a route trav-erse made in Alaska in 1898 by Mr. W. J. Peters of theUnited States Geological Survey. This is the first authenticsurvey of that region and was made with plane-table and ali- 88 GEOGRAPHIC AND EXPLORATORY Fig. 23.—Field Plaxe-takle Sheet. Exploratory Route Survey. J. Peters, Topographer. Scale i to EXAMPLES OF EXPLORATORY SURVEYS, 89
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