Projections
Only a globe can represent the world without distortion. Once a map is projected from
a sphere onto a two dimensional plane, it always incurs distortion in one or more of the following:
distance, direction, scale and area.
EarthDesk supports the following map projections:
Equirectangular Projection
The simplest of projections. Points of latitude and longitude are projected onto a perfectly square grid.
Van Der Grinten Projection
In this projection, meridians are arcs, enclosing the world in a circle. Because of the large distortion near the poles, the projection is clipped above Greenland
and at the Northern extent of Antarctica. In recent times, this has become a popular replacement for the Mercator projection.
Miller Projection
This is a rectangular projection that avoids much of the distortion of the Mercator projection (see below), but
is not useful for navigation as both distance and direction are distorted.
Mercator Projection
Perhaps the best known of all protections, it was originally used in early navigation, since a straight line on the map
is a rhumb line (line of constant direction). Unfortunately, it also results in large distortions in polar areas.
Transverse Mercator Projection
This projection works very well for large areas that extend North-South and are relatively narrow East-West.
A common use is to view North and South America simultaneously.
Robinson Projection
Rather than using mathematical equations to calculate the projection, the Robinson projection uses a series of
numerical tables to make the world "look right." All aspects of the map incur some distortion.
Mollweide Projection
The Mollweide projection, used for world maps, is accurate in terms of area, but distorts shapes and directions.
The 90th meridians are circular arcs. Parallels are straight, but unequally spaced.
Hammer Projection
Like the Mollweide projection, the Hammer projection is "equal-area," but is less elongated East to West.
Sinusoidal Projection
Similar to the Mollweide in that it accurately reflects area, it works better for depicting areas with large
North to South extents.
Azimuthal Projection
Usually used for long range navigation, seismology and by radio operators, straight lines are Great Circle routes, indicating
true distance and direction and the shortest path between the two endpoints.
Globe Projection
Actually an orthographic projection, this view depicts the earth in perspective as it would appear from deep space.