Gringorten wanted to create a square map in order to efficiently use space (e.g. in printed articles). Moreover it should be equal-area and without massive distortions or interruptions of the continents.
In the image, the map is centered to 20° West.
Jump to different depiction of this projection:
Specified in [square brackets]: Actual size of the projection
(minus the black or white background). When marked with [≈], sizes with and without
background are approx. the same.