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Zorluk: ZorContour Lines and Relief Representation

On a topographical map drawn to a scale of 1:20,0001:20,000, a foot trail ascends continuously from Point A at a contour elevation of 150 m150\text{ m} to Point B at a contour elevation of 300 m300\text{ m}. If the straight-line map distance between Point A and Point B measures 15.0 cm15.0\text{ cm}, what is the average gradient of the slope from Point A to Point B?

  1. A
    1:101 : 10
  2. 1:201 : 20Cevap
  3. C
    1:2001 : 200
  4. D
    1:5001 : 500

Cevap

The average gradient of the slope from Point A to Point B is 1:201 : 20.
To determine topographic gradient, calculate the Vertical Interval (VI\text{VI}) as 300 m150 m=150 m300\text{ m} - 150\text{ m} = 150\text{ m}. Convert the map distance (15.0 cm15.0\text{ cm}) to ground distance using the map scale (1:20,0001:20,000): 15.0 cm×20,000=300,000 cm=3,000 m15.0\text{ cm} \times 20,000 = 300,000\text{ cm} = 3,000\text{ m}. The ratio VIHE=150 m3,000 m=120\frac{\text{VI}}{\text{HE}} = \frac{150\text{ m}}{3,000\text{ m}} = \frac{1}{20}, giving an average gradient of 1:201 : 20.

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1
Calculate the Vertical Interval (VI)
VI=300 m150 m=150 m\text{VI} = 300\text{ m} - 150\text{ m} = 150\text{ m}
The vertical interval represents the total vertical height gained between the starting contour line and the destination contour line.
2
Convert map distance to ground distance to determine the Horizontal Equivalent (HE)
HE=15.0 cm×20,000=300,000 cm=3,000 m\text{HE} = 15.0\text{ cm} \times 20,000 = 300,000\text{ cm} = 3,000\text{ m}
Using the map scale ratio of 1:20,0001:20,000, every 1 cm1\text{ cm} on the map corresponds to 20,000 cm20,000\text{ cm} (200 m200\text{ m}) on the actual terrain.
3
Compute the slope gradient ratio
Gradient=VIHE=150 m3,000 m=120=1:20\text{Gradient} = \frac{\text{VI}}{\text{HE}} = \frac{150\text{ m}}{3,000\text{ m}} = \frac{1}{20} = 1 : 20
Gradient expresses the ratio of vertical rise to horizontal distance when both measurements are expressed in identical units.

Anahtar Kavram

Topographic Slope Gradient Calculation
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