# 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

+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

+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.