Orienteering at school for ages 13-15, Chapter 20: TO UNDERSTAND HILLS AND VALLEYS

Posted by admin 07/10/2018 0 Comment(s) BOOK: Cool, Awesome and Educational! PART 2 (by Göran Andersson),

 TO UNDERSTAND HILLS AND VALLEYS

 

From 3D to 2D

On the following pages we focus on mountains and valleys, ridges and depressions, hills and pits. The three dimensional hill we will try to transform into a ”flat hill”. It should be drawn with help of contour lines.

 

     

 

 

 

     

 

High mountains and deep valleys

The world’s highest mountain is Mount Everest (8848 metres above sea level) located on the border between Nepal and China. The world’s deepest ocean grave is the Mariana Grave (11,034 metres below sea level) located in the Pacific Ocean, south of Japan. It is more than 12 miles (19,882 m) between the highest and the lowest place on Earth.

 

In Sweden, Kebnekaise, is the highest mountain (2097 metres above sea level), while the lowest land point can be found in Kristianstad, 2,41 metres below sea level.


All maps, including maps with hills, are drawn from a photograph or laser scanning which have been taken a few kilometres up in the air. With help of this “map” we try to translate the map into a real image. The previous page shows some examples of three-dimensional maps. These translations of reality are not quite to scale and are slightly distorted and they are therefore difficult to use for determining the position and direction. But they work great to understand how mountains and valleys relate to each other in the terrain.

 

     


In order to easily understand how a map with altitude formations works I will recommend to build a hill e.g. in the sandbox or using LEGO pieces that shown on the upper right of the page. You can also go outdoors to find a rock formation that is similar to a mountain in miniature (see the boulder). 

 

         


Common to these models is to understand the highest point, the steepest part, and the gently sloping part and to recognize what is uphill or downhill. Using the contour lines (brown colour) it will be easy to understand how hills and valleys, ridges and re-entrants appear in reality.

 

The peak from different directions

The “Globe Arena” in Stockholm and other round buildings have regular shape. They look the same no matter where you stand and look at them. Peaks or hills are very different. Hills and valleys are irregular.


The peak of Idre Fjäll; Städjan

Städjan is Sweden’s southernmost mountain top. The mountain is very steep. It is visible from all directions. The top of the hill extends in a north-south direction. Städjan has a higher peak in the north and lower in the south. The highest peak is 1131 metres above sea level.


Different directions

The photos A-C are showing Städjan from different directions. Photo A is taken from South to North, photo B is taken from North West to South East and photo C is taken from South West to North East. You see the mountain in three different directions. It’s hard to know whether it is the same mountain from the photos. However, on the map the mountain is the same no matter where you are.


10 or 2 metres contour interval

The height between each contour line at a mountain map is 10 metres. Similar distance at a school map is 1 or 2 metres.

 

Draw a map of a hill

In Hansbyn outside Dala-Husby in Sweden, where I live, there are a lot of boulders. I can choose which boulder I want. The boulder, photo on the right, I have chosen to draw a map of contour lines.

 

   
 

The boulder’s different shapes

The map of the boulder is a simplified picture of reality. The purpose of the map is to show different shapes of the boulder. The steep sides. The highest points. The deep notches. These are the key elements to draw first. Then I draw the smaller details, such as a small groove or protruding parts.

   

 

                                               


The contour lines

It is the same distance between the contour lines. It is steep where the contour lines are very close together. Longer distance between the contour lines shows that there is a flatter area. 

On most maps the fifth contour line is drawn with thicker line. Thanks to the thick contour lines you get a much better idea what the hills and valleys look like.


Test yourself!

On the following pages you will find some “Test yourself exercises.” You will understand better how the hills and valleys are drawn on a map.

 

Explanations of the map’s contour lines

 

A Hill, highest point

B Ridge or spur

C Terrace or plateau

D Re-entrant or valley, large

E Re-entrant or valley, small 

F Steepest part of the hill

 

 

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