Question

tour interval = 50 meters
what is the approximate gradient along the straight dashed line between points x and y?
a) 150 m/km
b) 50 m/km
c) 300 m/km
d) 100 m/km

Explanation:

Step1: Determine the elevation difference

Count the contour lines between \(X\) and \(Y\). The contour interval is \(50\) meters. Suppose there are \(3\) contour lines between them (visual estimate from the map - assume standard contour interpretation). The elevation difference \(\Delta h=3\times50 = 150\) meters.

Step2: Determine the horizontal distance

Use the scale. Assume the measured length on - map (using the scale bar \(0 - 5\) km) for the \(X - Y\) line is \(1.5\) km (visual estimate).

Step3: Calculate the gradient

Gradient formula is \(G=\frac{\Delta h}{d}\), where \(\Delta h\) is elevation difference and \(d\) is horizontal distance. \(G=\frac{150}{1.5}=100\) m/km.

Answer:

D. \(100\) m/km