Mr Daly

1
Mr Daly 31/03/2017 136 AM
Calculating the Gradient

• The grade of a slope is important to understand
  in walking, road building, roofers, landscapers,
  train track laying, etc.
• Calculating gradient in geography
• Gradient in geography is different to gradient in
  maths.
• It is always expressed as 1x, ie 14, or 11.
• the second number in the expression is run/rise,
  so the way to calculate is
• run/rise  (where the run and the rise are
  measured in the same units).
• Tricks and traps
• Not expressing the gradient in the form 1x
• using rise over run as in maths
• With a contour map, the contours are likely to
  be expressed in metres (for the rise) whereas the
  run is likely to be measured in km.

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Mr Daly 31/03/2017 136 AM
Calculating the Gradient
Gradient measures the steepness of a slope Step
1 Measure the rise (difference in height between
2 points) Step 2 Measure the run (the distance
between 2 points). Step 3 Make sure that you
convert the scale into metres Both the rise and
run need to be expressed in metres.
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Mr Daly 31/03/2017 136 AM
Calculating the Gradient
Say the rise is 42 metres and the run is 600
metres.
42m
600m
divided by
42m
equals
14.28
600m
The answer is then written
1

1428
The answer is written like this to show that for
every 1 metre up, you travel 14.28 metres across
4
Mr Daly 31/03/2017 136 AM
Calculating the Gradient
The gradient is the rate of change of a slope.
Another way to think of it is that gradients
measure steepness. This can also be shown as a
percentage. This then shows, how fast the slope
is increasing or decreasing
http//www.youtube.com/watch?v3QFJ_uv2mGw
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Mr Daly 31/03/2017 136 AM
Calculating the Gradient
Say the rise is 100 metres and the run is 200
metres.
100m
200m
divided by
100m
equals
2.00
200m
The answer is then written
1

2
The answer is written like this to show that for
every 1 metre up, you travel 2 metres across

1

2
20
The answer can also be written like this to show
you the grade of the slop
6
Slope Vertical Distance (Rise) Horizontal Distance (Run) Gradient Incline Grade
A 23m 115m 15 20
B 16m 151
C 28m 448m
D 564m 112
E 10m 130
F 480m 120
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Mr Daly 31/03/2017 136 AM
Types of Slopes
There are two main types of Geographical
slopes. They are Convex or Concave
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Mr Daly 31/03/2017 136 AM
Types of Slopes
If a slope is not Convex (A) and Concave (B), it
is then Linear (C)
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Mr Daly 31/03/2017 136 AM
Types of Slopes