safe.gis.interpolation1d module¶

Module for 1D interpolation

This module:

• provides piecewise constant (nearest neighbour) and bilinear interpolation
• is fast (based on numpy vector operations)
• depends only on numpy
• guarantees that interpolated values never exceed the two nearest neighbours
• handles missing values in domain sensibly using NaN
• is unit tested with a range of common and corner cases

See interpolation2d.py for documentation of the mathematical derivation used.

safe.gis.interpolation1d.interpolate1d(x, z, points, mode='linear', bounds_error=False)[source]¶

Fundamental 1D interpolation routine.

Parameters:	x (numpy.ndarray) – 1D array of x-coordinates on which to interpolate z (numpy.ndarray) – 1D array of values for each x points (numpy.ndarray) – 1D array of coordinates where interpolated values are sought mode (str) – Determines the interpolation order. Options are: ‘constant’ - piecewise constant nearest neighbour interpolation ‘linear’ - bilinear interpolation using the two nearest neighbours (default) bounds_error (bool) – Flag to indicate whether an exception will be raised when interpolated values are requested outside the domain of the input data. If False, nan is returned for those values.
Returns:	1D array with same length as points with interpolated values
Return type:	numpy.ndarry
Raises:	RuntimeError

..note::

Input coordinates x are assumed to be monotonically increasing, but need not be equidistantly spaced.

z is assumed to have dimension M where M = len(x).