metpy.calc.smooth_n_point(scalar_grid, n=5, passes=1)[source]

Filter with an n-point smoother.

  • scalar_grid (array-like or pint.Quantity) – N-dimensional scalar grid to be smoothed. If more than two axes, smoothing is only done along the last two.

  • n (int) – The number of points to use in smoothing, only valid inputs are 5 and 9. Defaults to 5.

  • passes (int) – The number of times to apply the filter to the grid. Defaults to 1.


array-like or pint.Quantity – The filtered scalar grid


This function is a close replication of the GEMPAK function SM5S and SM9S depending on the choice of the number of points to use for smoothing. This function can be applied multiple times to create a more smoothed field and will only smooth the interior points, leaving the end points with their original values (this function will leave an unsmoothed edge of size 1 around the data). If a masked value or NaN values exists in the array, it will propagate to any point that uses that particular grid point in the smoothing calculation. Applying the smoothing function multiple times will propogate NaNs further throughout the domain.

Examples using metpy.calc.smooth_n_point