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DISTORTIONS IN MAPS DUE TO PROJECTIONSProjecting Earth’s surface alwaysinvolves distortion:shapeareadistancedirection
AVOIDING DISTORTIONS IN PROJECTIONS1.PRESERVATION OF AREAFor 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 ) = 12.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
AVOIDING DISTORTIONS IN PROJECTIONS3. 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 :-