"In cartography, a map projection is any of a broad set of transformations employed to represent the curved two-dimensional surface of a globe on a plane."
A method of representing the 3D surface of the Earth on a 2D map.
Coordinate systems: Different coordinate systems are used to locate and map features on the earth's surface. Understanding the principles of different coordinate systems is essential when studying map projection.
Earth's shape: The earth's shape has a great impact on the way maps are projected. It is important to study the various aspects of the earth's shape such as the equator, poles, and curvature to understand how map projection affects map accuracy and representation.
Map projection categories: There are three categories of map projections: Cylindrical, conical, and azimuthal. Understanding the properties of each map projection category is essential when choosing the appropriate projection for specific mapping purposes.
Projection types: There are many different types of map projections, each with its own set of unique properties. Understanding the differences between different projection types and their applications is important when choosing the best projection for a specific purpose.
Distortion: All map projections introduce some amount of distortion when representing the curved surface of the Earth on a flat map. Understanding the different types of distortion and how they affect map accuracy and representation is important when choosing the best projection for a specific mapping purpose.
Map scale: Map scale is the ratio between the distances on a map and the corresponding distances on the Earth's surface. Different map scales affect the level of detail on a map and influence the choice of projection.
Map projection software: Various software tools are available to aid in the selection and creation of map projections. Understanding how to use such software tools is important when working with map projections.
Other applications: Map projections also have applications in areas such as satellite imagery, GPS, and geocaching. Understanding how these applications use map projections can help in the selection and creation of the best map projection for a specific purpose.
Azimuthal (Planar) Projection: This projection is centered either on the North or South pole or on the Equator, and places the Earth's surface on a flat plane that tangential to one of these points. The distortion increases as one moves away from the central point.
Conic Projection: This projection is formed by projecting the Earth's surface onto a cone, which is then flattened into a plane. The cone may be tangent to the Earth's surface at one or more points.
Cylindrical Projection: This projection is formed by projecting the Earth's surface onto a cylinder. The cylinder may be tangent to the Earth's surface at one or more points, or may encompass the whole Earth.
Zenithal (Polar) Projection: This projection is centered either on the North or South pole, and places the Earth's surface on a flat plane that is perpendicular to the direction of the center point. The distortion increases as one moves away from the central point.
Gnomonic Projection: This projection is formed by projecting the Earth's surface onto a flat plane that is tangent to the Earth's surface at a single point. This projection is useful for calculating great circle routes.
Lambert Conformal Conic Projection: This projection is formed by projecting the Earth's surface onto a cone that is tangent to the Earth's surface along two standard parallels. This projection is often used for regional maps.
Mercator Projection: This projection is formed by projecting the Earth's surface onto a cylinder that is tangent to the Equator. The scale is consistent along the Equator and distorts away from it, making it useful for navigation.
Polyconic Projection: This projection is formed by projecting the Earth's surface onto a series of cones that are tangent to the Earth's surface along multiple standard parallels. This projection is often used for producing topographic maps.
Robinson Projection: This projection is a compromise projection that attempts to balance the distortion of shape, area, and distance across the world map. It is often used for world maps and atlases.
Winkel Tripel Projection: This projection is a compromise projection that uses a combination of the equal-area and conformal properties to produce a balance of shape, area, and distance across the world map. It is often used for world maps and atlases.
"In a map projection, coordinates, often expressed as latitude and longitude, of locations from the surface of the globe are transformed to coordinates on a plane."
"Projection is a necessary step in creating a two-dimensional map and is one of the essential elements of cartography."
"All projections of a sphere on a plane necessarily distort the surface in some way and to some extent."
"Different map projections exist in order to preserve some properties of the sphere-like body at the expense of other properties."
"The study of map projections is primarily about the characterization of their distortions."
"There is no limit to the number of possible map projections."
"Projections are considered in several fields of pure mathematics, including differential geometry, projective geometry, and manifolds."
"Rather, any mathematical function that transforms coordinates from the curved surface distinctly and smoothly to the plane is a projection."
"The Earth and other large celestial bodies are generally better modeled as oblate spheroids."
"The surfaces of planetary bodies can be mapped even if they are too irregular to be modeled well with a sphere or ellipsoid."
"The most well-known map projection is the Mercator projection."
"This map projection has the property of being conformal."
"However, it has been criticized throughout the 20th century for enlarging regions further from the equator."
"Equal-area projections such as the Sinusoidal projection and the Gall–Peters projection show the correct sizes of countries relative to each other."
"The National Geographic Society and most atlases favor map projections that compromise between area and angular distortion."
"such as the Robinson projection"
"the Winkel tripel projection."
"Therefore, more generally, a map projection is any method of flattening a continuous curved surface onto a plane."
"Few projections in practical use are perspective."