map projection
A teacher points to a world map showing a map projection on the classroom wall.
Noun: A method of representing the three-dimensional surface of the Earth (or another celestial body) onto a two-dimensional plane, such as a flat map. This is achieved by using a systematic transformation of coordinates from the globe's spherical or ellipsoidal surface to a plane, typically based on a grid of lines of latitude and longitude.
The term "map projection" is used to describe the specific mathematical formula and resulting system used to create a flat representation of the curved Earth. It is a technical term in cartography (map-making) and geography. - When discussing the accuracy, distortions, or appropriate use of a map. - When comparing different methods for representing the Earth on a flat surface.
- The Mercator map projection is commonly used for navigation because it represents lines of constant course as straight segments.
- Choosing the right map projection is crucial for a world map to minimize distortions of area or shape.
- This atlas explains the properties and uses of different map projections.
- Projection Family: Many map projections belong to families based on the geometric surface used in the transformation (e.g., cylindrical, conical, azimuthal/planar).
- Projection Property: Map projections can preserve specific properties, such as:
- Conformal: Preserves local angles and shapes (e.g., Mercator).
- Equal-area (Equivalent): Preserves area measurements (e.g., Gall-Peters).
- Equidistant: Preserves distances from one or two points to all other points.
- Compromise: Attempts to balance various distortions (e.g., Robinson, Winkel tripel).
- Projection (noun): In this context, the act or result of projecting a globe's surface onto a plane. More generally, it can mean the presentation of an image on a surface.
- Cartographic Projection: A synonym for "map projection," emphasizing its use in cartography.
- Project (verb): To cause an image, light, or surface to fall onto another surface. This is the root action described by a "projection."
- Cartographic projection
- Distortion: An inevitable result of any map projection, referring to the misrepresentation of shape, area, distance, or direction.
- Graticule: The network of lines of latitude and longitude on which a map projection is built.
- Geoid / Ellipsoid: The models of the Earth's shape used as the basis for projections.
A teacher points to a world map showing a map projection on the classroom wall.
- a projection of the globe onto a flat map using a grid of lines of latitude and longitude