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

Equal Area Cylindrical

proj-string: +proj=cea

Named specializations

The Equal Area Cylindrical projection is sometimes known under other names when it is instanciated 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=1.5708r

See Projection Units for more information.

+lon_0=<value>

Longitude of projection center.

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=1.5708r

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.

Defaults to 0.0.

+y_0=<value>

False northing.

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