Compiled By: Rauf Tabassum
Introduction
Introduction
Map
projections are attempts to portray the surface of the earth or a portion of
the earth on a flat surface. Some distortions of conformality,
distance, direction, scale, and area always result from this process. Some
projections minimize distortions in some of these properties at the expense of
maximizing errors in others. Some projection are attempts to only moderately
distort all of these properties.
Conformality
When
the scale of a map at any point on the map is the same in any direction, the
projection is conformal. Meridians (lines of longitude) and parallels (lines of
latitude) intersect at right angles. Shape is preserved locally on conformal
maps.
Distance
A
map is equidistant when it portrays distances from the center of the projection
to any other place on the map.
Direction
A
map preserves direction when azimuths (angles from a point on a line to another
point) are portrayed correctly in all directions.
Scale
Scale
is the relationship between a distance portrayed on a map and the same distance
on the Earth.
Area
When
a map portrays areas over the entire map so that all mapped areas have the same
proportional relationship to the areas on the Earth that they represent, the
map is an equal-area map.
Different
map projections result in different spatial relationships between regions.
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