In map projections, which variant uses projection lines from infinity?

In map projections, which variant uses projection lines from infinity?

• A. Orthographic
• B. Gnomonic
• C. Mercator
• D. Stereographic

Answer: (A)

Projection lines from infinity correspond to parallel projection, where every line of sight is parallel to the others as if viewed from an infinitely distant point. This is orthographic projection. In this setup, points on the globe are projected onto the plane along parallel lines, giving a view that uses the same direction everywhere. The other variants involve lines emanating from finite points (the sphere’s center for gnomonic, the opposite point on the sphere for stereographic, or a center-based perspective onto a cylinder for Mercator), so they do not use lines from infinity.

Projection lines from infinity correspond to parallel projection, where every line of sight is parallel to the others as if viewed from an infinitely distant point. This is orthographic projection. In this setup, points on the globe are projected onto the plane along parallel lines, giving a view that uses the same direction everywhere. The other variants involve lines emanating from finite points (the sphere’s center for gnomonic, the opposite point on the sphere for stereographic, or a center-based perspective onto a cylinder for Mercator), so they do not use lines from infinity.