equal-area projection
See Also: projection
[map projections] A projection in which the whole of the map as well as each part has the same proportional area as the corresponding part of the earth.
Cylindrical Equal-Area Projection
The map projection having transformation equations
(1) ...
A Lambert azimuthal equal-area projection of the Earth.
The Lambert azimuthal equal-area projection, or Lambert azimuthal projection, is an equal-area map projection.
equal-area projection
A projection in which the whole of the map as well as each part has the same proportional area as the corresponding part of the earth. An equal-area projection may distort shape, angle, scale, or any combination thereof.
The equal-area projection on a tangent cylinder - making the Equator a standard parallel in the normal aspect - was rigorously defined by Johann H. Lambert in both equatorial and transverse aspects, among several other projections (1772).
Suitable equal-area projections for distribution maps include those developed by Lambert, whether azimuthal, cylindrical, or conical. These do, however, have rather noticeable shape distortions.
Cylindrical Equal-Area projections have straight meridians and parallels, the meridians are equally spaced, the parallels unequally spaced. There are normal, transverse, and oblique cylindrical equal-area projections.
Sinusoidal Equal-Area Projection Map projection that represents areas in their true form on a two-dimensional map. Distances are only correct along parallels and central meridian.
Equal-area projections do not distort the size of areas but do distort their shapes. Conformal projections are those on which the scale is the same in any direction at any point on the map.
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Figure 4. Goode's Homolosine Equal-area Projection. (with the oceans interrupted to show the continents)
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Figure 5. Miller Cylindrical World Map Projection ...
A conformal projection primarily preserves shape, an equidistant projection primarily preserves distance, and an equal-area projection primarily preserves area.
These images show the earth using several different projections: ...
stereographic projection
gnomic projection
Lambert's azimuthal equal-area projection
orthographic projection ...
Even when the data were accurately obtained, their projection can introduce distortions. Use equal-area projections for area measurements that need high accuracy. Use projections which locally have small length distortions for distance measurements.
Invented in 1772 by Johann Heinrich Lambert with along with 6 other projections. Prototype for Behrmann and other modified cylindrical equal-area projections.
based on which measurement properties are most important to your work. For example, if it is very important to obtain accurate area measurements (e.g., for determining the home range of an animal species), you will select an equal-area projection.
also has a projection, a way of translating the three-dimensional real surface of the geoid to a two-dimensional picture. The most commonly used is the Mercator Projection; other popular projections are polar and a variety of equal-area projections.
Conformal projections preserve angular relationships, and better preserve arc-length, while equal-area projections are more appropriate for statistical studies and work in which the amount of material is important.
Equal-area projections, such as the Goode homolosine, typically have non-straight longitudes and may have unusual outlines.
 See also: Area, Equal-area, Map, Projection, Map Projection
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