map proj lesson-2 - DISTORTIONS IN MAPS DUE TO PROJECTIONS Projecting Earths surface always involves distortion shape area distance direction AVOIDING

map proj lesson-2 - DISTORTIONS IN MAPS DUE TO PROJECTIONS...

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DISTORTIONS IN MAPS DUE TO PROJECTIONS Projecting Earth’s surface always involves distortion: shape area distance direction
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AVOIDING DISTORTIONS IN PROJECTIONS 1. PRESERVATION OF AREA For some purposes it is important that areas should be represented in correct proportions . A map which possesses this property is called Equal Area or Equivalent. This can be achieved if the product of the scale factors in the two perpendicular directions at right angles remains unity. SF ( X ) X SF ( Y ) = 1 2.PRESERVATION OF SHAPE (CONFORMALITY)It is not possible to represent the shape of a large area of earth’s surface correctly upon a flat map, but on a topographical map it is important to obtain a best possible representation of shape because distances and bearings must be measured in any direction to a reliable standard.This can be achieved if:- a. The scale factor along the meridians and along the parallels are equal.b. The meridians and parallels intersect at right angles on the projection. l
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AVOIDING DISTORTIONS IN PROJECTIONS 3. ACCURACY OF BEARINGProjections selected for the construction of charts for long range navigation by sea or air must permit rapid and accurate plotting of bearings . Hence the projection should be :-
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  • Spring '17
  • Abdul Jabbar
  • Map projection, Mercator projection

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