Map Projection

A map projection is a way to represent the curved surface of the Earth on the flat surface of a map. A good globe can provide the most accurate representation of the Earth. However, a globe isn’t practical for many of the functions for which we require maps. Map projections allow us to represent some or all of the Earth’s surface, at a wide variety of scales, on a flat, easily transportable surface, such as a sheet of paper. Map projections also apply to digital map data, which can be presented on a computer screen.

There are hundreds of different map projections. The process of transferring information from the Earth to a map causes every projection to distort at least one aspect of the real world – either shape, area, distance, or direction.

Each map projection has advantages and disadvantages; the appropriate projection for a map depends on the scale of the map, and on the purposes for which it will be used. For example, a projection may have unacceptable distortions if used to map the entire country, but may be an excellent choice for a large-scale (detailed) map of a county. The properties of a map projection may also influence some of the design features of the map. Some projections are good for small areas, some are good for mapping areas with a large east-west extent, and some are better for mapping areas with a large north-south extent.

Some projections have special properties. For example, a Mercator projection has straight rhumb lines and is therefore excellent for navigation, because compass courses are easy to determine.

Developable Surface

The cylinder is an example of developable surface. In mathematics, a developable surface is a surface with zero Gaussian curvature. That is, it is a surface that can be flattened onto a plane without distortion . Conversely, it is a surface which can be made by transforming a plane (i.e. “folding”, “bending”, “rolling”, “cutting” and/or “gluing”). In three dimensions all developable surfaces are ruled surfaces (but not vice versa). There are developable surfaces in R4 which are not ruled.


About Rashid Faridi

I am Rashid Aziz Faridi ,Writer, Teacher and a Voracious Reader.
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One Response to Map Projection

  1. Pingback: PROJECTIONS | Rashid's Blog

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