Central Meridian: Straight line 0.51 as long as the Equator.
Other Meridians: Equally spaced, resemble elliptical arcs and are concave toward the central meridian.
Parallels: Straight parallel lines, perpendicular to the central meridian. Spacing is equal between the 38º parallels, decreasing outside these limits.
Poles: Lines 0.53 as long as the Equator.
Symmetry: About the central meridian or the Equator.
Scale is true along the 38º parallels and is constant along any parallel or between any pair of parallels equidistant from the Equator. It is not free of distortion at any point, but distortion is very low within about 45º of the center and along the Equator. This projection is not equal-area, conformal, or equidistant; however, it is considered to look right for world maps, and hence is widely used by Rand McNally, the National Geographic Society, and others. This feature is achieved through the use of tabular coordinates rather than mathematical formulae for the graticules.
For this projection, only one standard parallel is specified. The other standard parallel is the same latitude with the opposite sign. The standard parallel is by definition fixed at 38º.
This projection was presented by Arthur H. Robinson in 1963, and is also called the Orthophanic projection, which means right appearing.