windspharm.tools

Tools for managing data for use with VectorWind (or indeed spharm.Spharmt).

windspharm.tools.prep_data(data, dimorder)

Prepare data for input to VectorWind (or to spharm.Spharmt method calls).

Returns a dictionary of intermediate information that can be passed to recover_data or get_recovery to recover the original shape and order of the data.

Arguments:

data

Data array. The array must be at least 2D.

dimorder

String specifying the order of dimensions in the data array. The characters ‘x’ and ‘y’ represent longitude and latitude respectively. Any other characters can be used to represent other dimensions.

Returns:

pdata

data reshaped/reordered to (latitude, longitude, other).

info

A dictionary of information required to recover data.

See also:

recover_data, get_recovery.

Examples:

Prepare an array with dimensions (12, 17, 73, 144) where the dimensions are (time, level, latitude, longitude):

pdata, info = prep_data(data, 'tzyx')

Prepare an array with dimensions (144, 16, 73, 21) where the first dimension is longitude and the third dimension is latitude. The characters used to represent the other dimensions are arbitrary:

pdata, info = prep_data(data, 'xayb')

windspharm.tools.recover_data(pdata, info)

Recover the shape and dimension order of an array output from VectorWind methods (or from spharm.Spharmt methods).

This function performs the opposite of prep_data.

For recovering the shape of multiple variables, see get_recovery.

Arguments:

pdata

Data array with either 2 or 3 dimensions. The first two dimensions are latitude and longitude respectively.

info

Information dictionary output from prep_data.

Returns:

data

The data reshaped/reordered.

See also:

prep_data, get_recovery.

Example:

Recover the original input shape and dimension order of an array processed with prep_data or an output of VectorWind or sparm.Spharmt method calls on such data:

data = recover_data(pdata, info)

windspharm.tools.get_recovery(info)

Return a function that can be used to recover the shape and dimension order of multiple arrays output from VectorWind methods (or from spharm.Spharmt methods) according to a single dictionary of recovery information.

Argument:

info

Information dictionary output from prep_data.

Returns:

recover

A function used to recover arrays.

See also:

recover_data, prep_data.

Example:

Generate a function to recover the original input shape and dimension order of arrays processed with prep_data and outputs of VectorWind method calls on this data:

u, info = prep_data(u, 'tzyx')
v, info = prep_data(v, 'tzyx')
w = VectorWind(u, v)
sf, vp = w.sfvp()
recover = get_recovery(info)
u, v, sf, vp = recover(u, v, sf, vp)

windspharm.tools.reverse_latdim(u, v, axis=0)

Reverse the order of the latitude dimension of zonal and meridional wind components.

Arguments:

u, v

Zonal and meridional wind components respectively.

Optional argument:

axis

Index of the latitude dimension. This dimension will be reversed in the input arrays. Defaults to 0 (the first dimension).

Returns:

ur, vr

Zonal and meridional wind components with the latitude dimensions reversed. These are always copies of the input.

See also:

order_latdim.

Examples:

Reverse the dimension corresponding to latitude when it is the first dimension of the inputs:

u, v = reverse_latdim(u, v)

Reverse the dimension corresponding to latitude when it is the third dimension of the inputs:

u, v = reverse_latdim(u, v, axis=2)

windspharm.tools.order_latdim(latdim, u, v, axis=0)

Ensure the latitude dimension is north-to-south.

Returns copies of the latitude dimension and wind components with the latitude dimension going from north to south. If the latitude dimension is already in this order then the output will just be copies of the input.

Arguments:

latdim

Array of latitude values.

u, v

Zonal and meridional wind components respectively.

Keyword argument:

axis

Index of the latitude dimension in the zonal and meridional wind components. Defaults to 0 (the first dimension).

Returns:

latdimr

Possibly reversed latdim, always a copy of latdim.

ur, vr

Possibly reversed u and v respectively. Always copies of u and v respectively.

See also:

reverse_latdim.

Examples:

Order the latitude dimension when latitude is the first dimension of the wind components:

latdim, u, v = order_latdim(latdim, u, v)

Order the latitude dimension when latitude is the third dimension of the wind components:

latdim, u, v = order_latdim(latdim, u, v, axis=2)