def sigma_fltr(dem, n=3):
    """sigma * factor filter
    
    Useful for outlier removal

    These are min/max percentile ranges for different sigma values:
    1: 15.865, 84.135
    2: 2.275, 97.725
    3: 0.135, 99.865
    """
    std = dem.std()
    u = dem.mean()
    print('Excluding values outside of range: {1:0.2f} +/- {0}*{2:0.2f}'.format(n, u, std))
    rangelim = (u - n*std, u + n*std)
    out = range_fltr(dem, rangelim)
    return out
def sigma_fltr ( dem , n = 3 ) : std = dem . std ( ) u = dem . mean ( ) print ( 'Excluding values outside of range: {1:0.2f} +/- {0}*{2:0.2f}' . format ( n , u , std ) ) rangelim = ( u - n * std , u + n * std ) out = range_fltr ( dem , rangelim ) return out
sigma * factor filter
    
    Useful for outlier removal

    These are min/max percentile ranges for different sigma values:
    1: 15.865, 84.135
    2: 2.275, 97.725
    3: 0.135, 99.865