1. Contours
These slides will slowly tell you about contours wait until you see the NEXT  button to move on.
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Click the NEXT only when you are ready to move onto the next slide

2. Relief or shape of the land is shown by Contours
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Contours are those light brown or orange lines you can see on OS maps.
A contour line is an imaginary line that joins points of equal height above sea level.
The lines are numbered giving the height above sea level in metres.
On an OS 1:50000 map the contours will be drawn for every 10 metre rise. Although on this map they are every 3m so always remember to check.
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3. What use are contours?
They can be used to learn about the shape of the land (the relief).
A map with only a few contour lines will be flat (and often low lying)
If a map has lots of contours it is a mountainous or hilly area.
The actual pattern of the lines will tell you more detail about the area too.
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4. Let’s have a look at why that is.
It is important to remember that the closer together the contour lines the steeper the slope.
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Steep slopes
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Area that is flatter with only a gentle slope
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Let’s have a look at why that is.
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5. This is the side view of a hill.
Let’s see where this hill reaches these heights
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Now let’s plot those points
Now if we plotted those points on paper.
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Sea level
See how these lines are closer together on the steeper slope
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6. Let’s look at some other examples
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7. Think where is the steepest slope on this island?
Click here to see if you’re right
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8. . 76 Steepest slope – contour lines are closest together xxx
Sparrow point 227
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Sometimes spot heights can be shown as a dot with a note of the height of that particular place.
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A trigonometrical point (or trig point) shows the highest point in an area (in meters) and is shown as a blue triangle
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9. You can spot other features by the shape and pattern of the contours
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10. A valley may look like this…
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Often with a river running down through the valley
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11. However a spur can look very similar !90
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But here the heights are increasing in the opposite direction – always double check which way the contours are increasing or decreasing.
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12. Valley
Spur
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13. Now Try your hand at a short test or click on the return button to re-run this presentation.
For test
click here
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