Topographic surveying; including geographic, exploratory, and military mapping, with hints on camping, emergency surgery, and photography . direction of the slopes and in such manneras to horizontally encircle them in bands, and the width ofthese is intended to represent equal vertical heights. In order, therefore, to construct a IiacJiurc map it is neces-sary to sketch approximate contour lines (Fig. 141), the dis-tance between any two of these representing approximately afixed vertical distance. Between these contour lines and atright angles to them are drawn the hachure lines, the contoursb
Topographic surveying; including geographic, exploratory, and military mapping, with hints on camping, emergency surgery, and photography . direction of the slopes and in such manneras to horizontally encircle them in bands, and the width ofthese is intended to represent equal vertical heights. In order, therefore, to construct a IiacJiurc map it is neces-sary to sketch approximate contour lines (Fig. 141), the dis-tance between any two of these representing approximately afixed vertical distance. Between these contour lines and atright angles to them are drawn the hachure lines, the contoursbeing only penciled in and the hachures inked so that ultimate-ly the contour lines disappear. The hachure lines, as alreadystated, are not made continuous, but rest on the horizontal 462 TOPOGRAPHIC DRAWING. or contour curves, which are thus indicated by the termini ofthe hachure hues. In hachiiring a map the follo\vin<^ generaldirections are suggested : Commence with the Hghter slopes in the lightest line, inorder that the intensity of the tint may be increased withmore regularity. (Fig. 141.) When the projections of the m^ y-7 /. Fig. 141.—Hachure Construction. horizontal sections or contours are parallel the hachures areat right lines normal to both curv^es, but when they are notparallel the hachures radiate, their extremities being respec-tively normal to the curves at which they terminate. Hachuresare in sections or bands which should not be continuous withthe adjoining ones, but should terminate in the spaces be-tween them, thus accentuating the contour lines without ink-ing them. When the slope suddenly becomes abrupt thetint must be deepened by increasing the width of the hachurenear the extremities or by interpolating short lines betweenthe original hachures. Hachures are made shorter and widerfor steep slopes, and are lenghtened and narrowed as the in-clination decreases. CONVENTIONAL SIGNS 463 The first principle upon which hachures are constructed isthat the st
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