How are projections classified?

Answer 1

Coordinate projections can be classified in two main ways:

By the type of surface used for projection:

Cylindrical: A cylinder is imagined to wrap around the globe, and features are transferred onto it. (e.g., Mercator projection)

Conical: A cone is placed over the globe, and features are projected onto its surface. (e.g., Albers conical projection)

Planar (Azimuthal): A flat plane is used to project a specific portion of the globe. (e.g., Stereographic projection)

By the way the projection surface touches the globe:

Tangent: The projection surface touches the globe at only one line of contact.

Secant: The projection surface intersects the globe in two or more places.

Answer 2

Projections can be classified based on the type of map projection used (e.g., cylindrical, conic, azimuthal), the purpose of the projection (e.g., conformal, equal-area, equidistant), and the geometric properties they preserve (e.g., angles, distances, areas). Each classification has its own strengths and weaknesses depending on the specific application.