Applied Geomorphology Lecture Notes By David T Allison

Applied Geomorphology Lecture Notes By David T. Allison

Topographic Maps Scale (Relational Fraction; Graphical) Elevation contours (Relative to M. S. L) Boundary (Latitude & Longitude) Color (Water bodies, Woodlands, etc. ) Cultural Features (man-made features)

$Scale Relational fraction n n n 1: 24, 000 1 inch on the map$

Scale Relational fraction n n n 1: 24, 000 1 inch on the map = 24, 000 inches in reality 1 inch on the map = 24, 000 inches x 1 foot/12 inches 1 inch on the map = 2000 feet x 1 mile/5280 ft 1 inch = 0. 378 miles

Graphical Scale Uses a graphical scale to indicate distances

Elevation Contours Contour lines (brown) n n Based on aerial photographs analyzed stereographically Must agree with benchmarks and spot elevations Contour interval: elevation change between adjacent contours Hachured contours indicate closed depressions

Construction of Topographic Contours of any parameter use a simple proportionality rule Contours should “V” in the upstream direction across valleys. flow 87 x 80 x 77 x 80 x

Topographic contours in 3 D

Topographic contours in 3 D cont.

Contours: can delineate geological contacts

Topographic Map Boundary Always consist of lines of latitude and longitude Contain tick marks of UTM and SPCS on the border 103 30’ 32 15’ 103 22’ 30’’ 32 15’ 7. 5’ Topographic Quadrangle border (1: 24, 000) 32 7’ 30’’ 103 30’ 32 7’ 30’’ 103 22’ 30’’

Topographic Map Colors Brown: topographic contours Green: Forest and/or wetlands White: cleared areas (i. e. pastures, etc. ) Black: Cultural features (buildings, roads) Red: Land office grid system (Township & Range system); Major road systems Magenta: Photo-revised areas Blue: water bodies

Topographic Map Examples

Map Coordinate Systems Land Office Grid system (Township & Range) Universal Transverse Mercator (UTM) State Plane Coordinate System (SPCS)

Land Office Grid System R 2 W R 1 E 6 miles R 2 E 6 1 7 12 18 13 T 1 S 19 24 T 2 S 30 25 31 36 T 2 N T 1 N State Capital 36 square miles Legal description of location: NE ¼ , SW ¼, section 22, T 2 S, R 2 E NW NE SE Target location

Land Office Grid Example: Benchmark 212: n NW ¼, NE ¼, sec. 36, T 3 S, R 3 W