iris.coord_systems¶
Definitions of coordinate systems.
In this module:
A coordinate system in the Albers Conical Equal Area projection.
- class
iris.coord_systems.
AlbersEqualArea
(latitude_of_projection_origin=None, longitude_of_central_meridian=None, false_easting=None, false_northing=None, standard_parallels=None, ellipsoid=None)[source]¶Constructs a Albers Conical Equal Area coord system.
Kwargs:
- latitude_of_projection_origin:
True latitude of planar origin in degrees. Defaults to 0.0 .
- longitude_of_central_meridian:
True longitude of planar central meridian in degrees. Defaults to 0.0 .
- false_easting:
X offset from planar origin in metres. Defaults to 0.0 .
- false_northing:
Y offset from planar origin in metres. Defaults to 0.0 .
- standard_parallels (number or iterable of 1 or 2 numbers):
The one or two latitudes of correct scale. Defaults to (20.0, 50.0).
- ellipsoid (
GeogCS
):If given, defines the ellipsoid.
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
xml_element
(doc, attrs=None)¶Default behaviour for coord systems.
false_easting
¶X offset from planar origin in metres.
false_northing
¶Y offset from planar origin in metres.
grid_mapping_name
= 'albers_conical_equal_area'¶
latitude_of_projection_origin
¶True latitude of planar origin in degrees.
longitude_of_central_meridian
¶True longitude of planar central meridian in degrees.
standard_parallels
¶The one or two latitudes of correct scale (tuple of 1 or 2 floats).
Abstract base class for coordinate systems.
- class
iris.coord_systems.
CoordSystem
[source]¶Abstract base class for coordinate systems.
- abstract
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
grid_mapping_name
= None¶
A geographic (ellipsoidal) coordinate system, defined by the shape of the Earth and a prime meridian.
- class
iris.coord_systems.
GeogCS
(semi_major_axis=None, semi_minor_axis=None, inverse_flattening=None, longitude_of_prime_meridian=None)[source]¶Creates a new GeogCS.
Kwargs:
- semi_major_axis, semi_minor_axis:
Axes of ellipsoid, in metres. At least one must be given (see note below).
- inverse_flattening:
Can be omitted if both axes given (see note below). Defaults to 0.0 .
- longitude_of_prime_meridian:
Specifies the prime meridian on the ellipsoid, in degrees. Defaults to 0.0 .
If just semi_major_axis is set, with no semi_minor_axis or inverse_flattening, then a perfect sphere is created from the given radius.
If just two of semi_major_axis, semi_minor_axis, and inverse_flattening are given the missing element is calculated from the formula: \(flattening = (major - minor) / major\)
Currently, Iris will not allow over-specification (all three ellipsoid parameters).
Examples:
cs = GeogCS(6371229) pp_cs = GeogCS(iris.fileformats.pp.EARTH_RADIUS) airy1830 = GeogCS(semi_major_axis=6377563.396, semi_minor_axis=6356256.909) airy1830 = GeogCS(semi_major_axis=6377563.396, inverse_flattening=299.3249646) custom_cs = GeogCS(6400000, 6300000)
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
grid_mapping_name
= 'latitude_longitude'¶
inverse_flattening
¶\(1/f\) where \(f = (a-b)/a\).
longitude_of_prime_meridian
¶Describes ‘zero’ on the ellipsoid in degrees.
semi_major_axis
¶Major radius of the ellipsoid in metres.
semi_minor_axis
¶Minor radius of the ellipsoid in metres.
A geostationary satellite image map projection.
- class
iris.coord_systems.
Geostationary
(latitude_of_projection_origin, longitude_of_projection_origin, perspective_point_height, sweep_angle_axis, false_easting=None, false_northing=None, ellipsoid=None)[source]¶Constructs a Geostationary coord system.
Args:
- latitude_of_projection_origin:
True latitude of planar origin in degrees.
- longitude_of_projection_origin:
True longitude of planar origin in degrees.
- perspective_point_height:
Altitude of satellite in metres above the surface of the ellipsoid.
- sweep_angle_axis (string):
The axis along which the satellite instrument sweeps - ‘x’ or ‘y’.
Kwargs:
- false_easting:
X offset from planar origin in metres. Defaults to 0.0 .
- false_northing:
Y offset from planar origin in metres. Defaults to 0.0 .
- ellipsoid (
GeogCS
):If given, defines the ellipsoid.
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
xml_element
(doc, attrs=None)¶Default behaviour for coord systems.
false_easting
¶X offset from planar origin in metres.
false_northing
¶Y offset from planar origin in metres.
grid_mapping_name
= 'geostationary'¶
latitude_of_projection_origin
¶True latitude of planar origin in degrees.
longitude_of_projection_origin
¶True longitude of planar origin in degrees.
perspective_point_height
¶Altitude of satellite in metres.
sweep_angle_axis
¶The sweep angle axis (string ‘x’ or ‘y’).
A coordinate system in the Lambert Azimuthal Equal Area projection.
- class
iris.coord_systems.
LambertAzimuthalEqualArea
(latitude_of_projection_origin=None, longitude_of_projection_origin=None, false_easting=None, false_northing=None, ellipsoid=None)[source]¶Constructs a Lambert Azimuthal Equal Area coord system.
Kwargs:
- latitude_of_projection_origin:
True latitude of planar origin in degrees. Defaults to 0.0 .
- longitude_of_projection_origin:
True longitude of planar origin in degrees. Defaults to 0.0 .
- false_easting:
X offset from planar origin in metres. Defaults to 0.0 .
- false_northing:
Y offset from planar origin in metres. Defaults to 0.0 .
- ellipsoid (
GeogCS
):If given, defines the ellipsoid.
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
xml_element
(doc, attrs=None)¶Default behaviour for coord systems.
false_easting
¶X offset from planar origin in metres.
false_northing
¶Y offset from planar origin in metres.
grid_mapping_name
= 'lambert_azimuthal_equal_area'¶
latitude_of_projection_origin
¶True latitude of planar origin in degrees.
longitude_of_projection_origin
¶True longitude of planar origin in degrees.
A coordinate system in the Lambert Conformal conic projection.
- class
iris.coord_systems.
LambertConformal
(central_lat=None, central_lon=None, false_easting=None, false_northing=None, secant_latitudes=None, ellipsoid=None)[source]¶Constructs a LambertConformal coord system.
Kwargs:
- central_lat:
The latitude of “unitary scale”. Defaults to 39.0 .
- central_lon:
The central longitude. Defaults to -96.0 .
- false_easting:
X offset from planar origin in metres. Defaults to 0.0 .
- false_northing:
Y offset from planar origin in metres. Defaults to 0.0 .
- secant_latitudes (number or iterable of 1 or 2 numbers):
Latitudes of secant intersection. One or two. Defaults to (33.0, 45.0).
- ellipsoid (
GeogCS
):If given, defines the ellipsoid.
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
xml_element
(doc, attrs=None)¶Default behaviour for coord systems.
central_lat
¶True latitude of planar origin in degrees.
central_lon
¶True longitude of planar origin in degrees.
false_easting
¶X offset from planar origin in metres.
false_northing
¶Y offset from planar origin in metres.
grid_mapping_name
= 'lambert_conformal_conic'¶
secant_latitudes
¶The standard parallels of the cone (tuple of 1 or 2 floats).
A coordinate system in the Mercator projection.
- class
iris.coord_systems.
Mercator
(longitude_of_projection_origin=None, ellipsoid=None, standard_parallel=None)[source]¶Constructs a Mercator coord system.
Kwargs:
- longitude_of_projection_origin:
True longitude of planar origin in degrees. Defaults to 0.0 .
- ellipsoid (
GeogCS
):If given, defines the ellipsoid.
- standard_parallel:
The latitude where the scale is 1. Defaults to 0.0 .
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
xml_element
(doc, attrs=None)¶Default behaviour for coord systems.
grid_mapping_name
= 'mercator'¶
longitude_of_projection_origin
¶True longitude of planar origin in degrees.
standard_parallel
¶The latitude where the scale is 1.
A Specific transverse mercator projection on a specific ellipsoid.
- class
iris.coord_systems.
OSGB
[source]¶A Specific transverse mercator projection on a specific ellipsoid.
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
xml_element
(doc, attrs=None)¶Default behaviour for coord systems.
false_easting
¶X offset from planar origin in metres.
false_northing
¶Y offset from planar origin in metres.
grid_mapping_name
= 'transverse_mercator'¶
latitude_of_projection_origin
¶True latitude of planar origin in degrees.
longitude_of_central_meridian
¶True longitude of planar origin in degrees.
scale_factor_at_central_meridian
¶Scale factor at the centre longitude.
An orthographic map projection.
- class
iris.coord_systems.
Orthographic
(latitude_of_projection_origin, longitude_of_projection_origin, false_easting=None, false_northing=None, ellipsoid=None)[source]¶Constructs an Orthographic coord system.
Args:
- latitude_of_projection_origin:
True latitude of planar origin in degrees.
- longitude_of_projection_origin:
True longitude of planar origin in degrees.
Kwargs:
- false_easting:
X offset from planar origin in metres. Defaults to 0.0 .
- false_northing:
Y offset from planar origin in metres. Defaults to 0.0 .
- ellipsoid (
GeogCS
):If given, defines the ellipsoid.
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
xml_element
(doc, attrs=None)¶Default behaviour for coord systems.
false_easting
¶X offset from planar origin in metres.
false_northing
¶Y offset from planar origin in metres.
grid_mapping_name
= 'orthographic'¶
latitude_of_projection_origin
¶True latitude of planar origin in degrees.
longitude_of_projection_origin
¶True longitude of planar origin in degrees.
A coordinate system with rotated pole, on an optional GeogCS
.
- class
iris.coord_systems.
RotatedGeogCS
(grid_north_pole_latitude, grid_north_pole_longitude, north_pole_grid_longitude=None, ellipsoid=None)[source]¶Constructs a coordinate system with rotated pole, on an optional
GeogCS
.Args:
- grid_north_pole_latitude:
The true latitude of the rotated pole in degrees.
- grid_north_pole_longitude:
The true longitude of the rotated pole in degrees.
Kwargs:
- north_pole_grid_longitude:
Longitude of true north pole in rotated grid, in degrees. Defaults to 0.0 .
- ellipsoid (
GeogCS
):If given, defines the ellipsoid.
Examples:
rotated_cs = RotatedGeogCS(30, 30) another_cs = RotatedGeogCS(30, 30, ellipsoid=GeogCS(6400000, 6300000))
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
grid_mapping_name
= 'rotated_latitude_longitude'¶
grid_north_pole_latitude
¶The true latitude of the rotated pole in degrees.
grid_north_pole_longitude
¶The true longitude of the rotated pole in degrees.
north_pole_grid_longitude
¶Longitude of true north pole in rotated grid in degrees.
A stereographic map projection.
- class
iris.coord_systems.
Stereographic
(central_lat, central_lon, false_easting=None, false_northing=None, true_scale_lat=None, ellipsoid=None)[source]¶Constructs a Stereographic coord system.
Args:
- central_lat:
The latitude of the pole.
- central_lon:
The central longitude, which aligns with the y axis.
Kwargs:
- false_easting:
X offset from planar origin in metres. Defaults to 0.0 .
- false_northing:
Y offset from planar origin in metres. Defaults to 0.0 .
- true_scale_lat:
Latitude of true scale.
- ellipsoid (
GeogCS
):If given, defines the ellipsoid.
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
xml_element
(doc, attrs=None)¶Default behaviour for coord systems.
central_lat
¶True latitude of planar origin in degrees.
central_lon
¶True longitude of planar origin in degrees.
false_easting
¶X offset from planar origin in metres.
false_northing
¶Y offset from planar origin in metres.
grid_mapping_name
= 'stereographic'¶
true_scale_lat
¶Latitude of true scale.
A cylindrical map projection, with XY coordinates measured in metres.
- class
iris.coord_systems.
TransverseMercator
(latitude_of_projection_origin, longitude_of_central_meridian, false_easting=None, false_northing=None, scale_factor_at_central_meridian=None, ellipsoid=None)[source]¶Constructs a TransverseMercator object.
Args:
- latitude_of_projection_origin:
True latitude of planar origin in degrees.
- longitude_of_central_meridian:
True longitude of planar origin in degrees.
Kwargs:
- false_easting:
X offset from planar origin in metres. Defaults to 0.0 .
- false_northing:
Y offset from planar origin in metres. Defaults to 0.0 .
- scale_factor_at_central_meridian:
Reduces the cylinder to slice through the ellipsoid (secant form). Used to provide TWO longitudes of zero distortion in the area of interest. Defaults to 1.0 .
- ellipsoid (
GeogCS
):If given, defines the ellipsoid.
Example:
airy1830 = GeogCS(6377563.396, 6356256.909) osgb = TransverseMercator(49, -2, 400000, -100000, 0.9996012717, ellipsoid=airy1830)
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
xml_element
(doc, attrs=None)¶Default behaviour for coord systems.
false_easting
¶X offset from planar origin in metres.
false_northing
¶Y offset from planar origin in metres.
grid_mapping_name
= 'transverse_mercator'¶
latitude_of_projection_origin
¶True latitude of planar origin in degrees.
longitude_of_central_meridian
¶True longitude of planar origin in degrees.
scale_factor_at_central_meridian
¶Scale factor at the centre longitude.
A vertical/near-side perspective satellite image map projection.
- class
iris.coord_systems.
VerticalPerspective
(latitude_of_projection_origin, longitude_of_projection_origin, perspective_point_height, false_easting=None, false_northing=None, ellipsoid=None)[source]¶Constructs a Vertical Perspective coord system.
Args:
- latitude_of_projection_origin:
True latitude of planar origin in degrees.
- longitude_of_projection_origin:
True longitude of planar origin in degrees.
- perspective_point_height:
Altitude of satellite in metres above the surface of the ellipsoid.
Kwargs:
- false_easting:
X offset from planar origin in metres. Defaults to 0.0 .
- false_northing:
Y offset from planar origin in metres. Defaults to 0.0 .
- ellipsoid (
GeogCS
):If given, defines the ellipsoid.
as_cartopy_projection
()[source]¶Return a cartopy projection representing our native map.
This will be the same as the
as_cartopy_crs()
for map projections but for spherical coord systems (which are not map projections) we use a map projection, such as PlateCarree.
xml_element
(doc, attrs=None)¶Default behaviour for coord systems.
false_easting
¶X offset from planar origin in metres.
false_northing
¶Y offset from planar origin in metres.
grid_mapping_name
= 'vertical_perspective'¶
latitude_of_projection_origin
¶True latitude of planar origin in degrees.
longitude_of_projection_origin
¶True longitude of planar origin in degrees.
perspective_point_height
¶Altitude of satellite in metres.