Shape distortion increases at the poles. The Robinson projection is based on tables of coordinates, not mathematical formulas. The projection distorts shape, area, scale, and distance in an attempt to balance the errors of projection properties. Sinusoidal equal-area maps have straight parallels at right angles to a central meridian. Other meridians are sinusoidal curves.
Scale is true only on the central meridian and the parallels.
Conic A conic projection that distorts scale and distance except along standard parallels. Areas are proportional and directions are true in limited areas. Albers Equal-Area Conic Equidistant Conic Direction, area, and shape are distorted away from standard parallels. Used for portrayals of areas near to, but on one side of, the equator. Equidistant Conic Lambert Conformal Conic Area, and shape are distorted away from standard parallels.