RotatedLatLonGrid

class unifhy.RotatedLatLonGrid(grid_latitude, grid_longitude, grid_latitude_bounds, grid_longitude_bounds, grid_north_pole_latitude, grid_north_pole_longitude, north_pole_grid_longitude=0.0)

Bases: unifhy.space.Grid

This class characterises the spatial dimension for a Component as a regular grid on a spherical domain whose coordinates are latitudes and longitudes, and whose rotation axis is not aligned with the North pole. Its ellipsoid and datum are those of WGS 84 (see EPSG:4326).

Instantiation

Parameters

grid_latitude: one-dimensional array-like object

The array of latitude coordinates in degrees defining a spatial dimension of the domain. May be any type that can be cast to a numpy.ndarray. Must contain numerical values.

Parameter example:

grid_latitude=[0.88, 0.44, 0., -0.44, -0.88]

grid_longitude: one-dimensional array-like object

The array of longitude coordinates in degrees defining a spatial dimension of the domain. May be any type that can be cast to a numpy.ndarray. Must contain numerical values.

Parameter example:

grid_longitude=[-2.5, -2.06, -1.62, -1.18]

grid_latitude_bounds: two-dimensional array-like object

The array of latitude coordinate bounds in degrees defining the extent of the grid cell around the coordinate. May be any type that can be cast to a numpy.ndarray. Must be two dimensional with the first dimension equal to the size of grid_latitude and the second dimension equal to 2. Must contain numerical values.

Parameter example:

grid_latitude_bounds=[[1.1, 0.66], [0.66, 0.22],
                      [0.22, -0.22], [-0.22, -0.66],
                      [-0.66, -1.1]]

grid_longitude_bounds: two-dimensional array-like object

The array of longitude coordinate bounds in degrees defining the extent of the grid cell around the coordinate. May be any type that can be cast to a numpy.ndarray. Must be two dimensional with the first dimension equal to the size of grid_longitude and the second dimension equal to 2. Must contain numerical values.

Parameter example:

grid_longitude_bounds=[[-2.72, -2.28], [-2.28, -1.84],
                       [-1.84, -1.4], [-1.4, -0.96]]

grid_north_pole_latitude: int or float

The true latitude (i.e. in EPSG:4326) of the north pole of the rotated grid in degrees North. This parameter is required to project the rotated grid into a true latitude-longitude coordinate system.

grid_north_pole_longitude: int or float

The true longitude (i.e. in EPSG:4326) of the north pole of the rotated grid in degrees East. This parameter is required to project the rotated grid into a true latitude-longitude coordinate system.

north_pole_grid_longitude: int or float, optional

The longitude of the true north pole (i.e. in EPSG:4326) in the rotated grid in degrees. This parameter is optional to project the rotated grid into a true latitude-longitude coordinate system. If not provided, set to default value 0.

Examples

Instantiate 2D grid using lists:

>>> sd = RotatedLatLonGrid(
...     grid_latitude=[-0.88, -0.44, 0., 0.44, 0.88],
...     grid_longitude=[-2.5, -2.06, -1.62, -1.18],
...     grid_latitude_bounds=[[-1.1, -0.66], [-0.66, -0.22], [-0.22, 0.22],
...                           [0.22, 0.66], [0.66, 1.1]],
...     grid_longitude_bounds=[[-2.72, -2.28], [-2.28, -1.84],
...                            [-1.84, -1.4], [-1.4, -0.96]],
...     grid_north_pole_latitude=38.0,
...     grid_north_pole_longitude=190.0,
... )
>>> print(sd)
RotatedLatLonGrid(
    shape {Y, X}: (5, 4)
    Y, grid_latitude (5,): [-0.88, ..., 0.88] degrees
    X, grid_longitude (4,): [-2.5, ..., -1.18] degrees
    Y_bounds (5, 2): [[-1.1, ..., 1.1]] degrees
    X_bounds (4, 2): [[-2.72, ..., -0.96]] degrees
)

Methods

Construction

`from_extent_and_resolution`	Instantiate a `RotatedLatLonGrid` from the extent and the resolution of grid_latitude and grid_longitude coordinates (and optional altitude coordinates).
`from_field`	Instantiate a `RotatedLatLonGrid` from spatial dimension coordinates of a `cf.Field`.

Comparison

`is_space_equal_to`	Compare equality between the RotatedLatLonGrid and the spatial (X, Y, and Z) dimension coordinate in a `cf.Field`.
`spans_same_region_as`	Compare equality in region spanned between the RotatedLatLonGrid and another instance of RotatedLatLonGrid.
`is_matched_in`	Determine whether the horizontal cell bounds of the grid are overlapping with the cell bounds of another instance of `Grid`.

Utility

route

Move the given values from their current location in the Grid to their downstream/downslope location according to the flow_direction property of Grid.

Attributes

`shape`	Return the size of the `Grid` dimension axes as a `tuple`.
`axes`	Return the name of the properties to use to get access to the axes defined for the `Grid` instance as a `tuple`.
`X`	Return the X-axis of the `Grid` instance as a `cf.Data` instance.
`Y`	Return the Y-axis of the `Grid` instance as a `cf.Data` instance.
`X_bounds`	Return the bounds of the X-axis of the `Grid` instance as a `cf.Data` instance.
`Y_bounds`	Return the bounds of the Y-axis of the `Grid` instance as a `cf.Data` instance.
`X_name`	Return the name of the X-axis of the `Grid` instance as a `str`.
`Y_name`	Return the name of the Y-axis of the `Grid` instance as a `str`.
`land_sea_mask`	The land-sea mask for the `Grid` of boolean/binary values (i.e.
`flow_direction`	The information necessary to move any variable laterally (i.e.
`cell_area`	The horizontal area for the grid cells of the `Grid` in square metres given as a `cf.Field` and returned as a `numpy.ndarray`.