Airy¶

The Airy projection is an azimuthal minimum error projection for the region within the small or great circle defined by an angular distance, \(\phi_b\), from the tangency point of the plane \(( \lambda_0, \phi_0 )\).

Classification	Azimuthal
Available forms	Forward spherical projection
Defined area	Global
Alias	airy
Domain	2D
Input type	Geodetic coordinates
Output type	Projected coordinates

Options¶

+lat_b¶

Angular distance from tangency point of the plane \(( \lambda_0, \phi_0 )\) where the error is kept at minimum.

Defaults to 90° (suitable for hemispherical maps).

+no_cut¶: Do not cut at hemisphere limit

+lat_0=<value>¶

Latitude of natural origin, latitude of false origin or latitude of projection centre (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: +lat_0=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.

+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.

+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.