GCE O - LEVEL GEOGRAPHY MAP READING

In map work exercise, it is often very neccessary to copy, reduce or enlarge a map to a certain desired scale in order to stress on some facts.
Beltus

 MAP COPYING, REDUCTION AND ENLARGEMENT






GCE O - LEVEL GEOGRAPHY MAP READING


    In map work exercise, it is often very neccessary to copy, reduce or enlarge a map to a certain desired scale in order to stress on some facts. It is quite common to ask Geography students during an examination to either copy, reduce or enlarge a map.

MAP COPYING

     This is a ver simple forward exercise. In map copying the whole dimention of the map or outline of the Eastings and Northings are drawn on new sheet of  paper following the exact dimention of the original map. The interval between the grid lines, that is Eastings and the Northings remains thesame. The features required to be shown on the copied map are inserted in the new map exactly where there were as on the original map. If their positions are changed it will mean that thair position have also changed on the actual ground.
     Map copying can also be easily carried out with a tracing or transparent paper. In this case, the transparent paper is placed on the original map and the features asked to insert which are seen through the paper are then traced.
    During an examination, this tracing paper may not be allowed. But for the purpose of the execise it is allowed. After copying the map and inserting the features the scale must be inserted which should be exactly like that of the original map. A key should be inserted and the new title which must now be " copied map extract" of the original map title.

MAP REDUCTION

    This in another simple exercise in map work. When you are asked to reduce a map most often by half the scale of the original, the following steps should be taken.
  1. Measure the length and width of the map or the vertical and horizontal dimention of the map.
  2. Draw the dimention on your sheet of paper reducing it to half the scale by dividing the distance by two in eachj case.
  3. Measure the distance between the gridlines on the original map and divide by two. Then draw the new grids.
  4. Number the Eastings and the Northings maintaining the original numbering.
  5. Now insert all the physical and human features asked making sure that they are exactly in squares and points like in the original map. Conventional signs must be used to insert the features.
  6. Draw up a new scale. When a map is reduced by half, the scale of the original map is multiplied by two e.g 1:50000 on the original map becomes 1:100000 on the reduced map
  7. make a key and a new title of your map.
     It is possible to be asked to reduce the original map by 1/3 or by 1/4. If asked to reduce the map by 1/3, divide the original map by 3 and allow the follow the steps above and if by 1/4, divide the original map by 4 and follow the steps above. A the end of the exercise multiply scale by 3 or by 4.

MAP ENLARGEMENT

This is the representation of map features on aa larger area. Candidates are scarcely asked to enlarge the whole map but are often asked to enlarge a portion of a map say twice its size. To enlarge a particular section or portion of a map, the following steps should be followed.
  1. Identify the portion of the map to be enlarged by reading your grid reference value.
  2. Measure the length and width of the identified portion to be enlarged and multiply each by 2.
  3. Draw a new frame folowing the multiplied length and width on the sheet of paper.
  4. Insert the Eastings and Northings while maintaining the original numbering as on tyhe original map.
  5. Insert the physical and human features required on their rightful squares and positions as on the original map.
  6. Add a new scale by dividing the original by two e.g If the original scale is 1:50000, then the new scale of the enlarged portion becomes 1:25000.
  7. Give a new title and key to the enlarged portion by specifying the section enlarged.


   

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