pastas.stats.sgi.sgi
====================

.. py:function:: pastas.stats.sgi.sgi(series: pandas.Series, timescale_months: int = 1) -> pandas.Series

   
   Method to compute the Standardized Groundwater Index (SGI)
   :cite:t:`bloomfield_analysis_2013`.

   :param series: Pandas time series of the groundwater levels
                  for which the SGI is to be determined
   :type series: pandas.Series or Pandas.DataFrame
   :param timescale_months: Length of the aggregation period in months (default: 1; allowed: 1, 2, 3)
   :type timescale_months: integer, optional

   :returns: **sgi_series** -- Pandas time series of the groundwater levels. Time series index should be a
             pandas DatetimeIndex.
   :rtype: pandas.Series or Pandas.DataFrame

   .. rubric:: Notes

   The Standardized Groundwater Index (SGI) is a non-parametric method to
   standardize groundwater levels. The SGI is calculated for each aggregation
   period within the year separately. The data within that period in all years
   in the series are used to determine the reference for which the index is
   calculated for each value in that period.
   The SGI is a dimensionless index and is used to compare groundwater levels
   across different wells. It may be useful to resample the time series to a
   monthly interval before computing the SGI.















   ..
       !! processed by numpydoc !!