1. Contours
These slides will slowly tell you about contours wait until
you see the NEXT button to move on.
NEXT
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 XXXX
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• Contours are those light
brown or orange lines you XXXXX
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 NEXT
remember to check.
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. • 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. NEXT
5. • This is the side view of a hill.
Let’s see where this hill reaches these heights
Now let’s plot those points XXXX
Now if we plotted those points on paper.
300m
250m
200m
150m
100m
Sea level
See how these lines are closer together on the steeper slope NEXT
7. Think where is the steepest slope on this island?
Click here to see if you’re right
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200
150
100
50
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8. Steepest slope –
contour lines are closest
together
xxx Sparrow point
227
200
. 76
150
100
50
Sometimes spot heights can be shown as a dot with a note of
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the height of that particular place. XXXX
A trigonometrical point (or trig point) shows the highest point in an
area (in meters) and is shown as a blue triangle NEXT
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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120
90
Often with a river running down through the valley
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11. However a spur can look very similar !
90
120
150
But here the heights are increasing in the opposite
direction – always double check which way the
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contours are increasing or decreasing.