1. Maps Countour

Topographic Map and their Interpretation

What is Map???

The presentation of three dimensional geographic objects/features in two dimensional plane can be described a map

Map preparation The real object or a feature can be projected to a two dimensional plane by using two type of projections: • Perspective Projection •Orthographic Projection

Perspective Projection Object to be projected

Plane of projection

123

1

2

3

Plane of Projection

Orthographic Projection

Object to be projected

Forms of contours 1. Evenly distributed contour denotes planar slope

200 m 400 600

600 m 200 m

400 400 600

2. Concave Contour Valley and Gully

200

3. Convex Contour Valley and Gully

Forms of contours Saddle

300 m

300 400 400 500 500

500 500 400

400 300

300 200

200

eGHofË

Closed contours

700 600 m

400 m 600

1. Peak 1. Depression

Contour Spacing

2. Gentle Slope 1. Steep Slope 3. Very Gentle Slope

Contour Spacing

100

1. Cliff

100 200 300

200 300 400

400

2. Overhang

Real map Valley and Spur

Drainage Pattern

1. Dendritic drainage

2. Parallel drainage

Drainage Pattern

3. Trellis drainage

4. Rectangular drainage

Drainage Pattern 5. Centripetal drainage

6. Radial drainage

Stream Order 1

1 1

1

1

1

2

2

1

2 3

4

1

2

3