unifhy.RotatedLatLonGrid.cell_area

RotatedLatLonGrid.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.

Parameters

areas: cf.Field

The field containing the horizontal grid cell area. The shape of the data array must be the same as the Grid. The field data must contain surface area values in square metres.

Returns

numpy.ndarray

The array containing the horizontal grid cell area values in square metres. If not set previously, computed automatically.

Examples

>>> grid = LatLonGrid.from_extent_and_resolution(
...     latitude_extent=(51, 55),
...     latitude_resolution=1,
...     longitude_extent=(-2, 1),
...     longitude_resolution=1
... )
>>> print(grid.cell_area)
[[7.69725703e+09 7.69725703e+09 7.69725703e+09]
 [7.52719193e+09 7.52719193e+09 7.52719193e+09]
 [7.35483450e+09 7.35483450e+09 7.35483450e+09]
 [7.18023725e+09 7.18023725e+09 7.18023725e+09]]
>>> print(grid)  
LatLonGrid(
    shape {Y, X}: (4, 3)
    Y, latitude (4,): [51.5, ..., 54.5] degrees_north
    X, longitude (3,): [-1.5, -0.5, 0.5] degrees_east
    Y_bounds (4, 2): [[51.0, ..., 55.0]] degrees_north
    X_bounds (3, 2): [[-2.0, ..., 1.0]] degrees_east
    cell_area (4, 3): [[7697257030.0..., ..., 7180237253.9...]] m2
)

>>> import numpy
>>> areas = grid.to_field()
>>> areas.set_data(numpy.array([[7.70e+09, 7.70e+09, 7.70e+09],
...                             [7.53e+09, 7.53e+09, 7.53e+09],
...                             [7.35e+09, 7.35e+09, 7.35e+09],
...                             [7.18e+09, 7.18e+09, 7.18e+09]]))
>>> areas.units = 'm2'
>>> grid.cell_area = areas
>>> print(grid.cell_area)
[[7.70e+09 7.70e+09 7.70e+09]
 [7.53e+09 7.53e+09 7.53e+09]
 [7.35e+09 7.35e+09 7.35e+09]
 [7.18e+09 7.18e+09 7.18e+09]]