BritishNationalGrid

class unifhy.BritishNationalGrid(projection_y_coordinate, projection_x_coordinate, projection_y_coordinate_bounds, projection_x_coordinate_bounds)

Bases: unifhy.space.Grid

This class characterises the spatial dimension for a Component as a regular grid on a cartesian domain whose coordinates are northings and eastings covering Great Britain and Northern Ireland (EPSG:27700).

Instantiation

Parameters

projection_y_coordinate: one-dimensional array-like object

The array of northing coordinates in metres defining a spatial dimension of the domain. May be any type that can be cast to a numpy.ndarray. Must contain numerical values. Coordinates must be ordered positively.

Parameter example:

projection_y_coordinate=[12500, 13500, 14500]

Parameter example:

projection_y_coordinate=numpy.arange(12500, 15500, 1000)

projection_x_coordinate: one-dimensional array-like object

The array of easting coordinates in metres defining a spatial dimension of the domain. May be any type that can be cast to a numpy.ndarray. Must contain numerical values. Coordinates must be ordered positively.

Parameter example:

projection_x_coordinate=(80500, 81500, 82500, 83500)

Parameter example:

projection_x_coordinate=numpy.arange(80500, 84500, 1000)

projection_y_coordinate_bounds: two-dimensional array-like object

The array of northing coordinate bounds in metres 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 projection_y_coordinate and the second dimension equal to 2. Must contain numerical values.

Parameter example:

projection_y_coordinate_bounds=[
    [12e3, 13e3], [13e3, 14e3], [14e3, 15e3]
]

Parameter example:

projection_y_coordinate_bounds=numpy.column_stack(
    (numpy.arange(12000, 15000, 1000),
     numpy.arange(13000, 16000, 1000))
)

projection_x_coordinate_bounds: two-dimensional array-like object

The array of easting coordinate bounds in metres 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 projection_x_coordinate and the second dimension equal to 2. Must contain numerical values.

Parameter example:

projection_x_coordinate_bounds=((80e3, 81e3), (81e3, 82e3),
                                (82e3, 83e3), (83e3, 84e3))

Parameter example:

projection_x_coordinate_bounds=numpy.column_stack(
    (numpy.arange(80000, 84000, 1000),
     numpy.arange(81000, 85000, 1000))
)

Examples

Instantiating a 2D grid:

>>> import numpy
>>> sd = BritishNationalGrid(
...     projection_y_coordinate=[12500, 13500, 14500],
...     projection_x_coordinate=(80500, 81500, 82500, 83500),
...     projection_y_coordinate_bounds=numpy.column_stack(
...         (numpy.arange(12000, 15000, 1000),
...          numpy.arange(13000, 16000, 1000))
...     ),
...     projection_x_coordinate_bounds=numpy.column_stack(
...         (numpy.arange(80000, 84000, 1000),
...          numpy.arange(81000, 85000, 1000))
...     )
... )
>>> print(sd)
BritishNationalGrid(
    shape {Y, X}: (3, 4)
    Y, projection_y_coordinate (3,): [12500, 13500, 14500] m
    X, projection_x_coordinate (4,): [80500, ..., 83500] m
    Y_bounds (3, 2): [[12000, ..., 15000]] m
    X_bounds (4, 2): [[80000, ..., 84000]] m
)

Methods

Construction

`from_extent_and_resolution`	Instantiate a `BritishNationalGrid` from the extent and the resolution of northing, easting coordinates.
`from_field`	Instantiate a `BritishNationalGrid` from spatial dimension coordinates of a `cf.Field`.

Comparison

`is_space_equal_to`	Compare equality between the BritishNationalGrid 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 SpaceDomain in square metres given as a `cf.Field` and returned as a `numpy.ndarray`.