What are Maps?
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Maps are models of reality.
Attempts to represent the two-dimensional curved surface of the earth a flat surface.
3D TO 2D
Maps are main data source for GIS data base.
Construction of Map
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Select Projection.
Select a model for the shape of the earth(Sphere or ellipsoid)
Transform geographic coordinates(Longitude and latitude) to plane coordinates
(Eastings and northings or x,y)
Reduction of scale
Using GIS software, we can change from one projection to another through computer.
Types of Map Projection-
The three basic types of Map Projection and there are lot of variants.
Azimuthal Projections In case of Azimuthal projection, when the sheet is not conical or cylindrical to
take the shape of the earth and if we try to represent the boundaries of the
countries, the countries in the center of the sheet will have true representation
and whereas at the corner or the margins will have different shapes and sizes.
Conical Representation
The latitudes will be represented as curve lines and longitudes will be as
radiating lines. Depending on the latitude of the country or the location of the
country, the shape of the area will take place.
Cylindrical Mercator Projection
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Vertical longitudes and horizontal latitudes
We get a uniform grade, where the countries in the middle get true
representation.
But the place on the poles gets distorted. The shape of Antarctica completely
changes or distorted representation.
Variations are there because each country is located uniquely. And each country
will like to have its true shape and size. Therefore, every country has its own
projection system.
Variations are there because each country is located uniquely. And each country will like to
have its true shape and size. Therefore, every country has its own projection system.