CONTOURS

What are contours? Imaginary lines Drawn on a map Connecting places Which are at equal altitude (height above sea level)

S U R T Q E P G D F B M A C L I J H O K N

238 240 252 276 263 297 279 280 300 317 320 285 325 314 289 309 298 280 254 281 264

238 240 240 252 260 276 260 263 300 297 280 279 280 .300 317 320 285 325 314 320 289 309 300 298 280 280 280 254 281 260 264

INDEX CONTOURS

INDEX CONTOURS

Characteristics of Contours All places on the contour line lie at the same altitude Contours never intersect each other Contour interval (difference between two successive contour values) is uniform throughout the map All contour values are multiples of the contour interval Height of any place on map can be determined

FORM LINES Drawn where it is not possible to draw contours and there is a prominent relief feature which is lesser in height than the contour interval

Spacing between contours Widely spaced contours Gentle slope Closely packed contours Steep slope Overlapping contours Vertical slope

Uniform Gentle Slope

Uniform Gentle Slope 320 280 300 260 240 220

Uniform Steep Slope

Uniform Steep Slope 260 320 300 180 200 220 240 140 160 280

Concave Slope

Concave Slope 240 220 320 260 300 280

Convex Slope

Convex Slope

Features of Contour Diagrams Spacing gives idea of slope Shape of contours resembles shape of relief feature in ariel view It is possible to visualise the shape of the relief feature

VISUALISATION

CONICAL HILL 320 300 280 260

ASYMMETRICAL HILL 320 300 280 260

CIRCULAR PLATEAU 320 300 280 260

RIDGE 320 300 280 260

SADDLE 320 300 280 260

V SHAPED VALLEY 320 340 300 280 260 240 220 200 180

WATERFALL 320 340 300 280 260 240 220 200

An Escarpment

CONTOURS: PAGE:71 9293: Ridge 9289: Ridge (uniform) 9390: Ridge (steep) PAGE: 72 9689: Saddle/ col 9489: Hill PAGE: 73 7975: Conical hill PAGE: 74 9284: Conical hill

PAGE:75. 9782: Escarpment. 9783: Col/ Saddle PAGE :83 PAGE:75 9782: Escarpment 9783: Col/ Saddle PAGE :83 1907: Cliff( very steep) 2012: River valley