Construction of A Map Projection
The creation of a map projection involves two steps:
- Selection of a model for the shape of the Earth or planetary body (usually choosing between a sphere or ellipsoid). Because the Earth's actual shape is irregular, information is lost in this step.
- Transformation of geographic coordinates (longitude and latitude) to Cartesian (x,y) or polar plane coordinates. Cartesian coordinates normally have a simple relation to eastings and northings defined on a grid superimposed on the projection.
Some of the simplest map projections are literally projections, as obtained by placing a light source at some definite point relative to the globe and projecting its features onto a specified surface. This is not the case for most projections, which are defined only in terms of mathematical formulae that have no direct geometric interpretation.
Read more about this topic: Map Projection
Famous quotes containing the words construction of, construction, map and/or projection:
“The construction of life is at present in the power of facts far more than convictions.”
—Walter Benjamin (1892–1940)
“The construction of life is at present in the power of facts far more than convictions.”
—Walter Benjamin (1892–1940)
“If all the ways I have been along were marked on a map and joined up with a line, it might represent a minotaur.”
—Pablo Picasso (1881–1973)
“My image is a statement of the symbols of the harsh, impersonal products and brash materialistic objects on which America is built today. It is a projection of everything that can be bought and sold, the practical but impermanent symbols that sustain us.”
—Andy Warhol (1928–1987)