contours nextnext click the next only when you are ready to move onto the next slide these slides...
Post on 21-Dec-2015
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![Page 1: Contours NEXTNEXT Click the NEXT only when you are ready to move onto the next slide These slides will slowly tell you about contours wait until you](https://reader035.vdocuments.site/reader035/viewer/2022081519/56649d605503460f94a41a91/html5/thumbnails/1.jpg)
Contours
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Click the NEXT only when you are ready to move onto the next slide
These slides will slowly tell you about contours wait until you see the NEXT button to move on.
![Page 2: Contours NEXTNEXT Click the NEXT only when you are ready to move onto the next slide These slides will slowly tell you about contours wait until you](https://reader035.vdocuments.site/reader035/viewer/2022081519/56649d605503460f94a41a91/html5/thumbnails/2.jpg)
Relief or shape of the land is shown by Contours
• 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. NEXT
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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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• It is important to remember that the closer together the contour lines the steeper the slope.
•Let’s have a look at why that is.
Steep slopes
Area that is flatter with only a gentle slope
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• This is the side view of a hill.
Sea level
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Let’s see where this hill reaches these heights
300m
Now let’s plot those points
See how these lines are closer together on the steeper slope NEXT
Now if we plotted those points on paper.
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Let’s look at some other examples
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![Page 7: Contours NEXTNEXT Click the NEXT only when you are ready to move onto the next slide These slides will slowly tell you about contours wait until you](https://reader035.vdocuments.site/reader035/viewer/2022081519/56649d605503460f94a41a91/html5/thumbnails/7.jpg)
Think where is the steepest slope on this island?
Click here to see if you’re right
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Sometimes spot heights can be shown as a dot with a note of the height of that particular place.
A trigonometrical point (or trig point) shows the highest point in an area (in meters) and is shown as a blue triangle
Steepest slope – contour lines are closest together
Sparrow point 227
. 76
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![Page 9: Contours NEXTNEXT Click the NEXT only when you are ready to move onto the next slide These slides will slowly tell you about contours wait until you](https://reader035.vdocuments.site/reader035/viewer/2022081519/56649d605503460f94a41a91/html5/thumbnails/9.jpg)
You can spot other features by the shape and pattern of the contours
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![Page 10: Contours NEXTNEXT Click the NEXT only when you are ready to move onto the next slide These slides will slowly tell you about contours wait until you](https://reader035.vdocuments.site/reader035/viewer/2022081519/56649d605503460f94a41a91/html5/thumbnails/10.jpg)
A valley may look like this…
Often with a river running down through the valley
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![Page 11: Contours NEXTNEXT Click the NEXT only when you are ready to move onto the next slide These slides will slowly tell you about contours wait until you](https://reader035.vdocuments.site/reader035/viewer/2022081519/56649d605503460f94a41a91/html5/thumbnails/11.jpg)
However a spur can look very similar !
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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Valley Spur
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Now Try your hand at a short test or click on the return button to re-run this
presentation.
RETURN
For test
click here