Understanding Map Projections

ROBINSON
Distance
Generally, scale is made true along latitudes 38° N
and S. Scale is constant along any given latitude and
for the latitude of the opposite sign.
LIMITATIONS
Neither conformal nor equal area. Useful only for
world maps.
USES AND APPLICATIONS
Developed for use in general and thematic world
maps.
The central meridian is 118° W.
DESCRIPTION
Also called Orthophanic.
Used by Rand McNally since the 1960s and by the
National Geographic Society since 1988 for general
and thematic world maps.
A compromise projection used for world maps.
PROJECTION METHOD
Pseudocylindrical. Meridians are equally spaced and
resemble elliptical arcs, concave toward the central
meridian. The central meridian is a straight line
0.51 times the length of the equator. Parallels are
equally spaced straight lines between 38° N and S;
spacing decreases beyond these limits. The poles are
0.53 times the length of the equator. The projection
is based on tabular coordinates instead of
mathematical formulas.
LINEAR GRATICULES
All parallels and the central meridian.
PROPERTIES
Shape
Shape distortion is very low within 45 degrees of the
origin and along the equator.
Area
Distortion is very low within 45 degrees of the origin
and along the equator.
Direction
Generally distorted.
Supported map projections• 81