What is this all about?
The ability to read how steep hills and valleys are is critical when viewing a topographic map. Cartographers (people who create maps) use lines to represent elevation in maps to show people how steep the terrain actually is. Think of these lines as imaginary segments of the Earth, whereby the lines represent how high or low a particular point of the map is compared to seal level.
The dough activity above simulates these segments that cartographers make of the Earth's surface. Look at the map your created. Notice how some lines are close together where as others are further apart. If you repeat the activity above but re-stack each segment as you might notice some patterns:
- The steep parts of your dough mountain show the lines being closer together.
- The less steep parts show lines being further spaced apart.
This is really handy, as effectively you can show cliffs as incredibly close lines squished together which stand out quite well on a two dimensional map, really handy when planning your next bushwalking trip!
You can create your own topographic maps by surveying your local surroundings using an altimeter and tape (or alternatively a smart phone and Google Maps!). Another way is to create a simple data set in Microsoft Excel to show students how the coordinates on a grid can create a three dimensional mountain.
3D topographic map activity using Microsoft Excel
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