1. Calculating the Gradient
Mr Daly
16/02/ :18 PM16/02/ :18 PM
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 1:x, ie 1:4, or 1:1.
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 1:x
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.
So, make sure the rise is also in km (ie 700m = 0.7km) before applying the formula. 1: run/rise

2. Calculating the Gradient
Mr Daly
16/02/ :18 PM16/02/ :18 PM
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.

3. Calculating the Gradient
Mr Daly
16/02/ :18 PM16/02/ :18 PM
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 :
14:28
The answer is written like this to show that for every 1 metre up, you travel metres across

4. Calculating the Gradient
Mr Daly
16/02/ :18 PM16/02/ :18 PM
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

5. Calculating the Gradient
Mr Daly
16/02/ :18 PM16/02/ :18 PM
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. Vertical Distance (Rise) Horizontal Distance (Run)
Slope
Vertical Distance (Rise)
Horizontal Distance (Run)
Gradient
Incline Grade A
23m
115m
1:5
20% B
16m
1:51 C
28m
448m D
564m
1:12 E
10m
1:30 F
480m
1:20

7. Mr Daly
16/02/ :18 PM16/02/ :18 PM
Types of Slopes
There are two main types of Geographical slopes.
They are Convex or Concave

8. If a slope is not Convex (A) and Concave (B), it is then Linear (C)
Mr Daly
16/02/ :18 PM16/02/ :18 PM
Types of Slopes
If a slope is not Convex (A) and Concave (B), it is then Linear (C)

9. Mr Daly
16/02/ :18 PM16/02/ :18 PM
Types of Slopes