How do map projections represent Earth’s curved surface on a flat map?

In cartography, a projection is a systematic method of representing the Earth’s curved surface on a flat map. Because it is mathematically impossible to represent a sphere on a plane without distortion, cartographers use various techniques to transpose meridians and parallels onto a flat surface.12

Most projections are categorized by their geometric derivation:2

• Cylindrical: The Earth is treated as a cylinder. The Mercator projection is the most famous example, where meridians and parallels appear as straight lines, making it useful for navigation despite significant size distortion near the poles.12
• Conic: The globe is projected onto a cone tangent to the Earth at a selected parallel, often used for large-scale map series.2
• Azimuthal: The Earth is pictured as a flattened disk tangent to a specific point. Depending on the perspective point, these include gnomonic, stereographic, or orthographic projections.2

While these methods help minimize specific distortions, only a globe can represent shapes and areas with true fidelity.2