Projections are a means of transferring information from a sphere to a flat surface.
There are three types of Projections:
Straight coordinate lines.
Horizontal parallels cross meridians at right angles.
Meridians equally spaced.
Scale is consistent along each parallel.
Severely distorted at the poles.
Accurate near the Equator.
Parallels and meridians (being straight lines) don’t consider the curvature of the Earth.
The most common projection seen is the Mercator.