Ptolemy’s 1st projection is also known as the plane chart or planispheric projection. It is an early cartographic technique by the Greco-Roman mathematician and geographer Claudius Ptolemy. Ptolemy’s work in geography forms the basis of modern cartography. His ideas are particularly clear in his seminal work, the Geographia (or Geography).
Overview of Ptolemy’s 1st Projection
Ptolemy’s 1st projection is a simple cylindrical projection where the Earth is represented as a flat plane. In this projection:
- Meridians (lines of longitude) are straight and equally spaced, running perpendicular to the Equator.
- Parallels (lines of latitude) are also straight lines, but unlike meridians, they are not equally spaced. The spacing between parallels increases as one moves away from the Equator toward the poles.

