Topographic maps and sketch mapping . Fig. 21a.—Mariners Compass. usual compass bearing graduation of the surveyor and wewould speak of the same line as having a bearing of N 22|° E,meaning that it is 22f° from the North toward the method of stating the direction is shown in (c).This is known as the azimuth method and the circumferenceis divided from 0 to 360°. The zero point, or zero azimuth, 40 WHAT A TOPOGRAPHIC MAP SHOWS in surveying, is usually taken as North, but in astronomicalwork azimuths are measured from the south point. Notethat when directions are given by azimuth, me
Topographic maps and sketch mapping . Fig. 21a.—Mariners Compass. usual compass bearing graduation of the surveyor and wewould speak of the same line as having a bearing of N 22|° E,meaning that it is 22f° from the North toward the method of stating the direction is shown in (c).This is known as the azimuth method and the circumferenceis divided from 0 to 360°. The zero point, or zero azimuth, 40 WHAT A TOPOGRAPHIC MAP SHOWS in surveying, is usually taken as North, but in astronomicalwork azimuths are measured from the south point. Notethat when directions are given by azimuth, measured froma zero direction agreed upon, it is necessary to state simplythe angle. Thus for the line mentioned above the azimuth. Fig. 21 b.—Surveyors Compass Method. is simplythree methods Mh0> The following comparison illustrates the Mariner NNESEby S wsw NW Surveyor N M\° ES 83$° ES 67J° W N45° W Azimuth 146f°147±°315° DIRECTION 41 To obtain the direction of a point B from a point A on amap place a piece of tracing paper over A and draw two lineson it showing both the north direction and the direction ofB. This may then be placed over (a), (6), or (c) of Fig. 21and the direction read off.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectcartogr, bookyear1920
