Definition

Noun: - A type of map projection: An orthomorphic projection is a specific method of representing the three-dimensional surface of the Earth (or another celestial body) on a two-dimensional map. Its defining characteristic is that it preserves angles locally, meaning the shapes of very small areas are rendered accurately and without distortion.

Usage and Examples

• Noun:
  • Cartographers often use an orthomorphic projection like the Mercator for navigation charts because it represents lines of constant course as straight lines.
  • While an orthomorphic projection maintains true shapes for infinitesimally small areas, the shapes of larger regions, like continents, can become significantly distorted.

Advanced Usage and Technical Notes

• Property of Conformality: "Orthomorphic projection" is synonymous with a conformal projection. The key property is conformality, meaning that at any point on the map, the scale is the same in every direction. This preserves the angles at which curves, such as meridians and parallels, intersect.
• Limitation: It is critical to understand that an orthomorphic projection preserves shape only at a point or over a very small area. It does not preserve area (equal-area property) or distance. Large features will experience areal distortion.

Variants and Related Terms

• Conformal projection: The more common modern term used interchangeably with "orthomorphic projection."
• Mercator projection: A famous and widely used example of an orthomorphic (conformal) projection.
• Lambert conformal conic projection: Another common example of a conformal map projection.

Synonyms

• Conformal map projection
• Angle-preserving projection

Antonyms / Contrasting Terms

• Equal-area projection (e.g., Albers conic projection): A projection that preserves the relative size of areas but distorts shape.
• Equidistant projection: A projection that preserves distances from one or two points to all other points, but distorts both shape and area.

Noun

1. a map projection in which a small area is rendered in its true shape