pysteps.utils.transformation.NQ_transform

pysteps.utils.transformation.NQ_transform(R, metadata=None, inverse=False, **kwargs)

The normal quantile transformation as in Bogner et al (2012). Zero rain vales are set to zero in norm space.

Parameters:

R : array-like

Array of any shape to be transformed.

metadata : dict, optional

Metadata dictionary containing the transform, zerovalue and threshold attributes as described in the documentation of pysteps.io.importers.

inverse : bool, optional

If set to True, it performs the inverse transform. False by default.

Returns:

R : array-like

Array of any shape containing the (back-)transformed units.

metadata : dict

The metadata with updated attributes.

Other Parameters:  

a : float, optional

The offset fraction to be used for plotting positions; typically in (0,1). The default is 0., that is, it spaces the points evenly in the uniform distribution.

References

Bogner, K., Pappenberger, field., and Cloke, H. L.: Technical Note: The normal quantile transformation and its application in a flood forecasting system, Hydrol. Earth Syst. Sci., 16, 1085-1094, https://doi.org/10.5194/hess-16-1085-2012, 2012.