Topographic maps and sketch mapping . ., which cover an area rather than a narrow line. The best method in using the sketch case is to do roadwork by traversing, and area work mainly by triangulation. The use of the traversing method for mapping a roadis illustrated by Fig. 56, which represents a portion of a roadwith principal bends at B, C and D. We would set up oursketch board at A, Fig. 56a and turn and clamp the boardso that its edges were about north and south as shown in thefigure and so that the length of the board is in the generaldirection of the road. We now select a point on the bo
Topographic maps and sketch mapping . ., which cover an area rather than a narrow line. The best method in using the sketch case is to do roadwork by traversing, and area work mainly by triangulation. The use of the traversing method for mapping a roadis illustrated by Fig. 56, which represents a portion of a roadwith principal bends at B, C and D. We would set up oursketch board at A, Fig. 56a and turn and clamp the boardso that its edges were about north and south as shown in thefigure and so that the length of the board is in the generaldirection of the road. We now select a point on the board, TRAVERSING 99 a, to represent the point A on the ground. Place a pin at thepoint a on the board and putting the triangular weighted sight-ing scale or alidade next to the pin turn the alidade so thatit points at the next point B. A pencil line may now bedrawn along the edge of the alidade, giving the direction ofB. The distance to B is then paced and the point b, repre-senting B on the map is found by plotting the paced distance. ^B Road (a)
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectcartogr, bookyear1920
