Orthographic

The orthographic projection is a perspective azimuthal projection centered around a given latitude and longitude.

Classification	Azimuthal
Available forms	Forward and inverse, spherical and ellipsoidal
Defined area	Global, although only one hemisphere can be seen at a time
Alias	ortho
Domain	2D
Input type	Geodetic coordinates
Output type	Projected coordinates

Note

Before PROJ 7.2, only the spherical formulation was implemented. If wanting to replicate PROJ < 7.2 results with newer versions, the ellipsoid must be forced to a sphere, for example by adding a +f=0 parameter.

Note

Parameters k_0 and alpha are added in PROJ 9.5.0

This projection method corresponds to EPSG:9840 (or EPSG:1130 with k_0 or alpha).

Parameters

Note

All parameters for the projection are optional.

+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.

+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.

+alpha=<value>

Added in version 9.5.0.

Azimuth clockwise from north at the center of projection.

Defaults to 0.0.

+k_0=<value>: Added in version 9.5.0: Scale factor. Determines scale factor used in the projection.

Defaults to 1.0.

+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.

+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.