CHAPTER V. 



SKETCHING. 



This, being by far the most important part of the work of map 

 making, should be done by the must competent man for this work in the 

 party — as a rule, by its chief. Besides the fact that he is presumably the 

 best sketcher in the party, there is another reason for requiring that he 

 should execute the sketching. He is held responsible for the quality of 

 the work, not only of the sketching, but also of the accuracy and the 

 sufficiency of the control. In the sketching of the map he has the best 

 possible opportunity for examining into the condition of the control and of 

 remedying any weaknesses. 



Upon the completion of the secondary triangulation, the traverse 

 work, and the measurement of heights within an area, which may be large 

 or small according to convenience — but preferably should comprise a quarter 

 sheet — he should cause all this control to be assembled upon one sheet. 

 The traverse lines with all points located from them should be adjusted to 

 the secondary locations, and all measurements of height should be plotted 

 upon this skeleton, thus presenting in complete form all the control within 

 tlie area. With this sheet upon a sketching board the chief of party 

 should go over the ground, sketching the drainage, culture, and forms of 

 relief. The latter should be sketched in actual continuous contours, direct 

 from the country as copy, so that upon leaving the sketching stations the 

 only work remaining to complete the map will be inking and lettering. In 

 heavy country, however, where the contours follow one another closely, it 

 may often be sufficient to put in on the stations only a part of the contours — 

 every fifth one, for instance — in order to economize time in the field. 

 Stations for sketching may be selected with the utmost freedom. An exact 

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