iris.coord_systems#

Definitions of coordinate systems.

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]#

Bases: CoordSystem

A coordinate system in the Albers Conical Equal Area projection.

Construct a Albers Conical Equal Area coord system.

Parameters:
  • latitude_of_projection_origin (optional) – True latitude of planar origin in degrees. Defaults to 0.0.

  • longitude_of_central_meridian (optional) – True longitude of planar central meridian in degrees. Defaults to 0.0.

  • false_easting (optional) – X offset from planar origin in metres. Defaults to 0.0.

  • false_northing (optional) – Y offset from planar origin in metres. Defaults to 0.0.

  • standard_parallels (number or iterable of 1 or 2 numbers, optional) – The one or two latitudes of correct scale. Defaults to (20.0, 50.0).

  • ellipsoid (GeogCS, optional) – If given, defines the ellipsoid.

__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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.

ellipsoid#

Ellipsoid definition (GeogCS or None).

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).

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.

class iris.coord_systems.CoordSystem[source]#

Bases: object

Abstract base class for coordinate systems.

__eq__(other)[source]#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

abstract as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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#
xml_element(doc, attrs=None)[source]#

Perform default behaviour for coord systems.

class iris.coord_systems.GeogCS(semi_major_axis=None, semi_minor_axis=None, inverse_flattening=None, longitude_of_prime_meridian=None)[source]#

Bases: CoordSystem

A geographic (ellipsoidal) coordinate system.

A geographic (ellipsoidal) coordinate system, defined by the shape of the Earth and a prime meridian.

Create a new GeogCS.

Parameters:
  • semi_major_axis (optional) – Axes of ellipsoid, in metres. At least one must be given (see note below).

  • semi_minor_axis (optional) – Axes of ellipsoid, in metres. At least one must be given (see note below).

  • inverse_flattening (optional) – Can be omitted if both axes given (see note below). Default 0.0.

  • longitude_of_prime_meridian (optional) – Specifies the prime meridian on the ellipsoid, in degrees. Default 0.0.

Notes

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).

After object creation, altering any of these properties will not update the others. semi_major_axis and semi_minor_axis are used when creating Cartopy objects.

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)
__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

as_cartopy_globe()[source]#
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.

property datum#
classmethod from_datum(datum, longitude_of_prime_meridian=None)[source]#
grid_mapping_name = 'latitude_longitude'#
property inverse_flattening#
longitude_of_prime_meridian#

Describes ‘zero’ on the ellipsoid in degrees.

property semi_major_axis#
property semi_minor_axis#
xml_element(doc)[source]#

Perform default behaviour for coord systems.

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]#

Bases: CoordSystem

A geostationary satellite image map projection.

Construct a Geostationary coord system.

Parameters:
  • 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 (str) – The axis along which the satellite instrument sweeps - ‘x’ or ‘y’.

  • false_easting (optional) – X offset from planar origin in metres. Defaults to 0.0.

  • false_northing (optional) – Y offset from planar origin in metres. Defaults to 0.0.

  • ellipsoid (GeogCS, optional) – If given, defines the ellipsoid.

__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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.

ellipsoid#

Ellipsoid definition (GeogCS or None).

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’).

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.

class iris.coord_systems.LambertAzimuthalEqualArea(latitude_of_projection_origin=None, longitude_of_projection_origin=None, false_easting=None, false_northing=None, ellipsoid=None)[source]#

Bases: CoordSystem

A coordinate system in the Lambert Azimuthal Equal Area projection.

Construct a Lambert Azimuthal Equal Area coord system.

Parameters:
  • latitude_of_projection_origin (optional) – True latitude of planar origin in degrees. Defaults to 0.0.

  • longitude_of_projection_origin (optional) – True longitude of planar origin in degrees. Defaults to 0.0.

  • false_easting (optional) – X offset from planar origin in metres. Defaults to 0.0.

  • false_northing (optional) – Y offset from planar origin in metres. Defaults to 0.0.

  • ellipsoid (GeogCS, optional) – If given, defines the ellipsoid.

__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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.

ellipsoid#

Ellipsoid definition (GeogCS or None).

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.

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.

class iris.coord_systems.LambertConformal(central_lat=None, central_lon=None, false_easting=None, false_northing=None, secant_latitudes=None, ellipsoid=None)[source]#

Bases: CoordSystem

A coordinate system in the Lambert Conformal conic projection.

Construct a LambertConformal coord system.

Parameters:
  • central_lat (optional) – The latitude of “unitary scale”. Defaults to 39.0 .

  • central_lon (optional) – The central longitude. Defaults to -96.0 .

  • false_easting (optional) – X offset from planar origin in metres. Defaults to 0.0.

  • false_northing (optional) – Y offset from planar origin in metres. Defaults to 0.0.

  • secant_latitudes (number or iterable of 1 or 2 numbers, optional) – Latitudes of secant intersection. One or two. Defaults to (33.0, 45.0).

  • ellipsoid (GeogCS, optional) – If given, defines the ellipsoid.

Notes

__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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.

central_lat#

True latitude of planar origin in degrees.

central_lon#

True longitude of planar origin in degrees.

ellipsoid#

Ellipsoid definition (GeogCS or None).

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).

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.

class iris.coord_systems.Mercator(longitude_of_projection_origin=None, ellipsoid=None, standard_parallel=None, scale_factor_at_projection_origin=None, false_easting=None, false_northing=None)[source]#

Bases: CoordSystem

A coordinate system in the Mercator projection.

Construct a Mercator coord system.

Parameters:
  • longitude_of_projection_origin (optional) – True longitude of planar origin in degrees. Defaults to 0.0.

  • ellipsoid (GeogCS, optional) – If given, defines the ellipsoid.

  • standard_parallel (optional) – The latitude where the scale is 1. Defaults to 0.0.

  • scale_factor_at_projection_origin (optional) – Scale factor at natural origin. Defaults to unused.

  • false_easting (optional) – X offset from the planar origin in metres. Defaults to 0.0.

  • false_northing (optional) – Y offset from the planar origin in metres. Defaults to 0.0.

  • datum (optional) – If given, specifies the datumof the coordinate system. Only respected if iris.Future.daum_support is set.

Notes

Only one of standard_parallel and scale_factor_at_projection_origin should be included.

__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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.

ellipsoid#

Ellipsoid definition (GeogCS or None).

false_easting#

X offset from the planar origin in metres.

false_northing#

Y offset from the planar origin in metres.

grid_mapping_name = 'mercator'#
longitude_of_projection_origin#

True longitude of planar origin in degrees.

standard_parallel#

The latitude where the scale is 1.

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.

class iris.coord_systems.OSGB[source]#

Bases: TransverseMercator

A Specific transverse mercator projection on a specific ellipsoid.

Construct a TransverseMercator object.

Parameters:
  • latitude_of_projection_origin – True latitude of planar origin in degrees.

  • longitude_of_central_meridian – True longitude of planar origin in degrees.

  • false_easting (optional) – X offset from planar origin in metres. Defaults to 0.0.

  • false_northing (optional) – Y offset from planar origin in metres. Defaults to 0.0.

  • scale_factor_at_central_meridian (optional) – 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, optional) – If given, defines the ellipsoid.

Examples

airy1830 = GeogCS(6377563.396, 6356256.909)
osgb = TransverseMercator(49, -2, 400000, -100000, 0.9996012717,
                          ellipsoid=airy1830)
__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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.

ellipsoid#

Ellipsoid definition (GeogCS or None).

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.

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.

class iris.coord_systems.ObliqueMercator(azimuth_of_central_line, latitude_of_projection_origin, longitude_of_projection_origin, false_easting=None, false_northing=None, scale_factor_at_projection_origin=None, ellipsoid=None)[source]#

Bases: CoordSystem

A cylindrical map projection, with XY coordinates measured in metres.

Designed for regions not well suited to Mercator or TransverseMercator, as the positioning of the cylinder is more customisable.

See also

RotatedMercator

ObliqueMercator with azimuth_of_central_line=90.

Construct an ObliqueMercator object.

Parameters:
  • azimuth_of_central_line (float) – Azimuth of centerline clockwise from north at the center point of the centre line.

  • latitude_of_projection_origin (float) – The true longitude of the central meridian in degrees.

  • longitude_of_projection_origin (float) – The true latitude of the planar origin in degrees.

  • false_easting (float, optional) – X offset from the planar origin in metres. Defaults to 0.0.

  • false_northing (float, optional) – Y offset from the planar origin in metres. Defaults to 0.0.

  • scale_factor_at_projection_origin (float, optional) – Scale factor at the central meridian. Defaults to 1.0 .

  • ellipsoid (GeogCS, optional) – If given, defines the ellipsoid.

Examples

>>> from iris.coord_systems import GeogCS, ObliqueMercator
>>> my_ellipsoid = GeogCS(6371229.0, None, 0.0)
>>> ObliqueMercator(90.0, -22.0, -59.0, -25000.0, -25000.0, 1., my_ellipsoid)
ObliqueMercator(azimuth_of_central_line=90.0, latitude_of_projection_origin=-22.0, longitude_of_projection_origin=-59.0, false_easting=-25000.0, false_northing=-25000.0, scale_factor_at_projection_origin=1.0, ellipsoid=GeogCS(6371229.0))
__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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.

azimuth_of_central_line#

Azimuth of centerline clockwise from north.

ellipsoid#

Ellipsoid definition (GeogCS or None).

false_easting#

X offset from planar origin in metres.

false_northing#

Y offset from planar origin in metres.

grid_mapping_name = 'oblique_mercator'#
latitude_of_projection_origin#

True latitude of planar origin in degrees.

longitude_of_projection_origin#

True longitude of planar origin in degrees.

scale_factor_at_projection_origin#

Scale factor at the central meridian.

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.

class iris.coord_systems.Orthographic(latitude_of_projection_origin, longitude_of_projection_origin, false_easting=None, false_northing=None, ellipsoid=None)[source]#

Bases: CoordSystem

An orthographic map projection.

Construct an Orthographic coord system.

Parameters:
  • latitude_of_projection_origin – True latitude of planar origin in degrees.

  • longitude_of_projection_origin – True longitude of planar origin in degrees.

  • false_easting (optional) – X offset from planar origin in metres. Defaults to 0.0.

  • false_northing (optional) – Y offset from planar origin in metres. Defaults to 0.0.

  • ellipsoid (GeogCS, optional) – If given, defines the ellipsoid.

__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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.

ellipsoid#

Ellipsoid definition (GeogCS or None).

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.

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.

class iris.coord_systems.PolarStereographic(central_lat, central_lon, false_easting=None, false_northing=None, true_scale_lat=None, scale_factor_at_projection_origin=None, ellipsoid=None)[source]#

Bases: Stereographic

A subclass of the stereographic map projection centred on a pole.

Construct a Polar Stereographic coord system.

Parameters:
  • central_lat ({90, -90}) – The latitude of the pole.

  • central_lon (float) – The central longitude, which aligns with the y axis.

  • false_easting (float, optional) – X offset from planar origin in metres.

  • false_northing (float, optional) – Y offset from planar origin in metres.

  • true_scale_lat (float, optional) – Latitude of true scale.

  • scale_factor_at_projection_origin (float, optional) – Scale factor at the origin of the projection.

  • ellipsoid (GeogCS, optional) – If given, defines the ellipsoid.

Notes

It is only valid to provide at most one of true_scale_lat and scale_factor_at_projection_origin.

__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()#

Return a cartopy CRS representing our native coordinate system.

as_cartopy_projection()#

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.

central_lat#

True latitude of planar origin in degrees.

central_lon#

True longitude of planar origin in degrees.

ellipsoid#

Ellipsoid definition (GeogCS or None).

false_easting#

X offset from planar origin in metres.

false_northing#

Y offset from planar origin in metres.

grid_mapping_name = 'polar_stereographic'#
scale_factor_at_projection_origin#

Scale factor at projection origin.

true_scale_lat#

Latitude of true scale.

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.

class iris.coord_systems.RotatedGeogCS(grid_north_pole_latitude, grid_north_pole_longitude, north_pole_grid_longitude=None, ellipsoid=None)[source]#

Bases: CoordSystem

A coordinate system with rotated pole, on an optional GeogCS.

Construct a coordinate system with rotated pole, on an optional GeogCS.

Parameters:
  • 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 (optional) – Longitude of true north pole in rotated grid, in degrees. Defaults to 0.0.

  • ellipsoid (GeogCS, optional) – If given, defines the ellipsoid.

Examples

rotated_cs = RotatedGeogCS(30, 30)
another_cs = RotatedGeogCS(30, 30,
                           ellipsoid=GeogCS(6400000, 6300000))
__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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.

ellipsoid#

Ellipsoid definition (GeogCS or None).

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.

xml_element(doc)[source]#

Perform default behaviour for coord systems.

class iris.coord_systems.RotatedMercator(latitude_of_projection_origin, longitude_of_projection_origin, false_easting=None, false_northing=None, scale_factor_at_projection_origin=None, ellipsoid=None)[source]#

Bases: ObliqueMercator

ObliqueMercator with azimuth_of_central_line=90.

As noted in CF versions 1.10 and earlier:

The Rotated Mercator projection is an Oblique Mercator projection with azimuth = +90.

Notes

Deprecated since version 3.8.0: This coordinate system was introduced as already scheduled for removal in a future release, since CF version 1.11 onwards now requires use of ObliqueMercator with azimuth_of_central_line=90. . Any RotatedMercator instances will always be saved to NetCDF as the oblique_mercator grid mapping.

Construct a RotatedMercator object.

Parameters:
  • latitude_of_projection_origin (float) – The true longitude of the central meridian in degrees.

  • longitude_of_projection_origin (float) – The true latitude of the planar origin in degrees.

  • false_easting (float, optional) – X offset from the planar origin in metres. Defaults to 0.0.

  • false_northing (float, optional) – Y offset from the planar origin in metres. Defaults to 0.0.

  • scale_factor_at_projection_origin (float, optional) – Scale factor at the central meridian. Defaults to 1.0 .

  • ellipsoid (GeogCS, optional) – If given, defines the ellipsoid.

__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()#

Return a cartopy CRS representing our native coordinate system.

as_cartopy_projection()#

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.

azimuth_of_central_line#

Azimuth of centerline clockwise from north.

ellipsoid#

Ellipsoid definition (GeogCS or None).

false_easting#

X offset from planar origin in metres.

false_northing#

Y offset from planar origin in metres.

grid_mapping_name = 'oblique_mercator'#
latitude_of_projection_origin#

True latitude of planar origin in degrees.

longitude_of_projection_origin#

True longitude of planar origin in degrees.

scale_factor_at_projection_origin#

Scale factor at the central meridian.

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.

class iris.coord_systems.Stereographic(central_lat, central_lon, false_easting=None, false_northing=None, true_scale_lat=None, ellipsoid=None, scale_factor_at_projection_origin=None)[source]#

Bases: CoordSystem

A stereographic map projection.

Construct a Stereographic coord system.

Parameters:
  • central_lat (float) – The latitude of the pole.

  • central_lon (float) – The central longitude, which aligns with the y axis.

  • false_easting (float, optional) – X offset from planar origin in metres.

  • false_northing (float, optional) – Y offset from planar origin in metres.

  • true_scale_lat (float, optional) – Latitude of true scale.

  • ellipsoid (GeogCS, optional) – If given, defines the ellipsoid.

  • scale_factor_at_projection_origin (float, optional) – Scale factor at the origin of the projection.

Notes

It is only valid to provide one of true_scale_lat and scale_factor_at_projection_origin

__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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.

central_lat#

True latitude of planar origin in degrees.

central_lon#

True longitude of planar origin in degrees.

ellipsoid#

Ellipsoid definition (GeogCS or None).

false_easting#

X offset from planar origin in metres.

false_northing#

Y offset from planar origin in metres.

grid_mapping_name = 'stereographic'#
scale_factor_at_projection_origin#

Scale factor at projection origin.

true_scale_lat#

Latitude of true scale.

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.

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]#

Bases: CoordSystem

A cylindrical map projection, with XY coordinates measured in metres.

Construct a TransverseMercator object.

Parameters:
  • latitude_of_projection_origin – True latitude of planar origin in degrees.

  • longitude_of_central_meridian – True longitude of planar origin in degrees.

  • false_easting (optional) – X offset from planar origin in metres. Defaults to 0.0.

  • false_northing (optional) – Y offset from planar origin in metres. Defaults to 0.0.

  • scale_factor_at_central_meridian (optional) – 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, optional) – If given, defines the ellipsoid.

Examples

airy1830 = GeogCS(6377563.396, 6356256.909)
osgb = TransverseMercator(49, -2, 400000, -100000, 0.9996012717,
                          ellipsoid=airy1830)
__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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.

ellipsoid#

Ellipsoid definition (GeogCS or None).

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.

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.

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]#

Bases: CoordSystem

A vertical/near-side perspective satellite image map projection.

Construct a Vertical Perspective coord system.

Parameters:
  • 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.

  • false_easting (optional) – X offset from planar origin in metres. Defaults to 0.0.

  • false_northing (optional) – Y offset from planar origin in metres. Defaults to 0.0.

  • ellipsoid (GeogCS, optional) – If given, defines the ellipsoid.

__eq__(other)#

Override equality.

The _globe and _crs attributes are not compared because they are cached properties and completely derived from other attributes. The nature of caching means that they can appear on one object and not on another despite the objects being identical, and them being completely derived from other attributes means they will only differ if other attributes that are being tested for equality differ.

as_cartopy_crs()[source]#

Return a cartopy CRS representing our native coordinate system.

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.

ellipsoid#

Ellipsoid definition (GeogCS or None).

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.

xml_element(doc, attrs=None)#

Perform default behaviour for coord systems.