CartesianLocalNED

class sargeom.coordinates.CartesianLocalNED(x, y, z, origin=None)

Bases: Cartesian3

A North-East-Down (NED) system uses the Cartesian coordinates (xNorth, yEast, zDown) to represent position relative to a local origin. The local origin is described by the geodetic coordinates (lat0, lon0, h0). Note that the origin does not necessarily lie on the surface of the ellipsoid.

Parameters:

xNorthfloat or numpy.ndarray

The positive X-axis points north along the meridian of longitude containing lon0, in meters.

yEastfloat or numpy.ndarray

The positive Y-axis points east along the parallel of latitude containing lat0, in meters.

zDownfloat or numpy.ndarray

The positive Z-axis points downward along the ellipsoid normal, in meters.

originsargeom.coordinates.Cartographic

The origin position in geodetic coordinates of the North-East-Down (NED) system.

Attributes:

rotationscipy.spatial.transform.Rotation

Get the 3D Rotation SciPy instance for transforming geocentric ECEF coordinates of a vector to local NED coordinates.

Examples

>>> CartesianLocalNED(10.0, 20.0, 30.0, origin=Cartographic.ONERA_SDP())
XYZ CartesianLocalNED point
[10. 20. 30.]

Attributes Summary

rotation

Get the 3D Rotation SciPy instance for transforming geocentric ECEF coordinates of a vector to local NED coordinates.

Methods Summary

save_csv(filename)	Saves the cartesian NED coordinates to a CSV file.
to_aer([degrees])	Transforms local North-East-Down (NED) coordinates to local Azimuth-Elevation-Range (AER) spherical coordinates.
to_ecef()	Converts local North-East-Down (NED) coordinates to Earth-centered Earth-fixed (ECEF) coordinates.
to_enu()	Converts local North-East-Down (NED) coordinates to local East-North-Up (ENU) coordinates.

Attributes Documentation

rotation

Get the 3D Rotation SciPy instance for transforming geocentric ECEF coordinates of a vector to local NED coordinates.

Returns:

scipy.spatial.transform.Rotation

The 3D Rotation SciPy instance.

Examples

>>> ned_coords = CartesianLocalNED(10.0, 20.0, 30.0, origin=Cartographic.ONERA_SDP())
>>> ned_coords.rotation.as_matrix() 
array([[-0.687..., -0.061...,  0.723...],
       [-0.089...,  0.996...,  0.        ],
       [-0.721..., -0.064..., -0.689...]])
>>> ned_coords.rotation.as_quat() 
array([-0.041...,  0.918..., -0.017...,  0.393...])

Methods Documentation

save_csv(filename)

Saves the cartesian NED coordinates to a CSV file.

Parameters:

filenamestr or pathlib.Path

The name of the file to save the coordinates.

Examples

>>> positions = CartesianLocalNED(x=10.0, y=20.0, z=30.0, origin=Cartographic.ONERA_SDP())
>>> positions.save_csv("positions.csv")

to_aer(degrees=True)

Transforms local North-East-Down (NED) coordinates to local Azimuth-Elevation-Range (AER) spherical coordinates. Both coordinate systems use the same local origin.

An azimuth-elevation-range (AER) system uses the spherical coordinates (az, elev, range) to represent position relative to a local origin. The local origin is described by the geodetic coordinates (lat0, lon0, h0). Azimuth, elevation, and slant range are dependent on the local ENU Cartesian system.

Parameters:

degreesbool, optional

If True (default), returns the angle in degrees. If False, returns the angle in radians.

Returns:

azimuthnumpy.ndarray

The azimuth, the clockwise angle in the xEast-yNorth plane from the positive yNorth-axis to the projection of the object into the plane.

elevationnumpy.ndarray

The elevation, the angle from the xEast-yNorth plane to the object.

slant_rangenumpy.ndarray

The slant range (in meters), the Euclidean distance between the object and the local origin.

Examples

>>> ned_coords = CartesianLocalNED(10.0, 20.0, 30.0, origin=Cartographic.ONERA_SDP())
>>> azimuth, elevation, slant_range = ned_coords.to_aer()
>>> print(f"{azimuth}°", f"{elevation}°", f"{slant_range}m") 
63.434...° 53.300...° 37.416...m

to_ecef()

Converts local North-East-Down (NED) coordinates to Earth-centered Earth-fixed (ECEF) coordinates.

Returns:

sargeom.coordinates.CartesianECEF

The geocentric ECEF coordinates.

Examples

>>> ned_coords = CartesianLocalNED(10.0, 20.0, 30.0, origin=Cartographic.ONERA_SDP())
>>> ned_coords.to_ecef() 
XYZ CartesianECEF point
[4606298.339...  412557.566... 4377546.319...]

to_enu()

Converts local North-East-Down (NED) coordinates to local East-North-Up (ENU) coordinates. Both coordinate systems use the same local origin.

Returns:

sargeom.coordinates.CartesianLocalENU

The local NED coordinates.

Examples

>>> ned_coords = CartesianLocalNED(10.0, 20.0, 30.0, origin=Cartographic.ONERA_SDP())
>>> ned_coords.to_enu()
XYZ CartesianLocalENU point
[ 20.  10. -30.]