. Elements of military sketching and map reading . Fig. 9. SOME SKETCHING INSTRUMENTS 21 order of the graduations on the face of a clock) is thebetter as it reduces chances of error in reading. At-tention is invited to the arrangements of the cardinalpoints on the dial of the box compass (Fig. 9). Notethat E is to the left of N. This reversion of E and W. Fig. II. Fig. 12. has been purposely made to facilitate the for example, assume the first course of a road tobe magnetic north. In this case the position of thecompass needle when taking the bearing will be as inFig. II. The road l
. Elements of military sketching and map reading . Fig. 9. SOME SKETCHING INSTRUMENTS 21 order of the graduations on the face of a clock) is thebetter as it reduces chances of error in reading. At-tention is invited to the arrangements of the cardinalpoints on the dial of the box compass (Fig. 9). Notethat E is to the left of N. This reversion of E and W. Fig. II. Fig. 12. has been purposely made to facilitate the for example, assume the first course of a road tobe magnetic north. In this case the position of thecompass needle when taking the bearing will be as inFig. II. The road later turns NW (Fig. i^). Atthis point sight In the new direction along the sighting 22 OF MILITARY SKETCHING line on the compass-box lid. The needle will leave jN and move toward W (on the dial). Take the read- \ing from N to the needle—so many degrees XW. -The index or north end of the needle has remained \fixed, while the sighting line of the compass has movedtowards the west (the new direction) and W on the icompass face has approached the needle. If a rever- \sion of the cardinal points E and W had not been ]made, the reading would obviously be more difficult,and it is very probable that the sketcher, while workingrapidly, would have read so many degrees NE if thisreversion were not clearly shown by lettering. CHAPTER IVORIENTATION
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