Equal Area Cylindrical

Classification	Cylindrical
Available forms	Forward and inverse, spherical and ellipsoidal
Defined area	Global
Alias	cea
Domain	2D
Input type	Geodetic coordinates
Output type	Projected coordinates

proj-string: +proj=cea

Named specializations

The Equal Area Cylindrical projection is sometimes known under other names when it is instantiated with particular values of the lat_ts parameter:

Name	lat_ts
Lambert cylindrical equal-area	0
Behrmann	30
Gall-Peters	45

Parameters

Note

All parameters are optional for the Equal Area Cylindrical projection.

+lat_ts=<value>

Latitude of true scale. Defines the latitude where scale is not distorted. Takes precedence over +k_0 if both options are used together.

Defaults to 0.0.

Note

The default convention is to interpret this value as decimal degrees. To specify radians instead, follow the value with the "r" character.

Example: +lat_ts=1.570796r

See Projection Units for more information.

+lon_0=<value>

Central meridian/longitude of natural origin, longitude of origin or longitude of false origin (naming and meaning depend on the projection method).

Defaults to 0.0.

Note

The default convention is to interpret this value as decimal degrees. To specify radians instead, follow the value with the "r" character.

Example: +lon_0=1.570796r

See Projection Units for more information.

+ellps=<value>

The name of a built-in ellipsoid definition.

See Ellipsoids for more information, or execute proj -le for a list of built-in ellipsoid names.

Defaults to "GRS80".

+R=<value>

Radius of the sphere, given in meters. If used in conjunction with +ellps, +R takes precedence.

See Ellipsoid size parameters for more information.

+k_0=<value>

Scale factor. Determines scale factor used in the projection.

Defaults to 1.0.

+x_0=<value>

False easting, easting at false origin or easting at projection centre (naming and meaning depend on the projection method). Always in meters.

Defaults to 0.0.

+y_0=<value>

False northing, northing at false origin or northing at projection centre (naming and meaning depend on the projection method). Always in meters.

Defaults to 0.0.

Note

lat_ts and k_0 are mutually exclusive. If lat_ts is specified, it is equivalent to setting k_0 to \(\frac{\cos \phi_{ts}}{\sqrt{1 - e^2 \sin^2 \phi_{ts}}}\)

Further reading

1. Wikipedia: Lambert cylindrical equal-area

2. Wikipedia: Gall-Peters

3. Wikipedia: Behrmann