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Unformatted text preview: 1 GY 301: Geomorphology GY 301: Geomorphology Lecture 4: Topographic Profiles UNIVERSITY OF SOUTH ALABAMA Last Time A Simple day; How to draw contour lines Computer contouring methods Contouring When starting. Use pencil Light pressure Start at the highest elevation do one line at a time Proportionality rule for contour spacing Chalk Board 163 162 150 138 143 158 146 133 140 127 125 117 120 103 135 102 174 155 170 163 184 130 CI=20 feet X Contour Maps (summary) - contour lines connect points of equal elevation - steep slopes are shown by closely spaced contour lines - gentle slopes are shown by widely spaced contour lines -contour lines do not intersect, branch or cross , except in a vertical or overhanging cliff. - when contour lines cross streams they bend upstream; the contour line forms a 'V' with the apex at the intersection with the stream, and pointing in an upstream direction (law of the Vs-mach one). Beware low gradient streams!...
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- Fall '10