F.1 Social Studies Enrichment Program 4

A point is written along each contour showing its heights Contours are lines joining places with the same height above the sea level. contour line. contour map A point is written along each contour showing its heights

Vertical Intervals of the map Interval: the distance between two things The difference in height between two adjacent contours is called Vertical Intervals (V.I.) of the map.

Put in the correct height values of contours in the blank

Cross section It is supposed a hill has been cut vertically, then we can see the side view, or cross section of the hill A section is a slice vertically down through the land. A cross section shows the shape of the lands.

Drawing a cross section First draw a line on the contour map from Point X to Point Y.

Drawing a cross section Mark all the contour lines and their heights between the two points Take a piece of paper and mark point X and point Y on the edge of the paper

Drawing a cross section Insert the scale and unit on X axis and Y axis. M

Drawing a cross section Plot all the points. M

Drawing a cross section Join all the points with a smooth line. M Do not forget to put down a title The hill

Gradient Gradient is another method to find the degree of steepness of a slope. It is obtained by using the formula: Vertical Interval (V.I.) Horizontal equivalent (H.E.) Horizontal distance between the bottom of slope and the top of the slope. It is called Horizontal Equivalent

Gradient The gradient of AB: 600m-200m (V.I.) 4.2 X 100m = 400m 420m = 1 - 1.05 We call it 1 in 1.105

Gradient The gradient of CD: 500m-200m (V.I.) 2.8 X 100m = 300m 280m = 1 - 0.98 We call it 1 in 0.98 Therefore, CD is steeper than AB

Gradient When contour lines are close together, the slope is steep. When contour lines are far apart, the slope is gentle.