bring all plots (x,y)
    to same x value base

def bringPlotOverSameX(data, nsample=None):
    """
    bring all plots (x,y)
    to same x value base
    """
    x0 = [x[0] for x, _ in data if len(x)]
    x1 = [x[-1] for x, _ in data if len(x)]

    xmin = min(np.min(x0), np.min(x1))
    xmax = max(np.max(x0), np.max(x1))

    if nsample is None:
        # calc from mean point density:
        pn_per_dist = np.mean([len(x) / (abs(x[0] - x[-1]))
                               for x, _ in data if len(x)])
        #...and max distance:
        nsample = round(pn_per_dist * abs(xmax - xmin))

    xArr = np.linspace(xmin, xmax, nsample)

    if x0[0] > x1[0]:
        # values are reverse sorted
        interpol = [np.interp(xArr, x[::-1], y[::-1],
                              left=np.nan, right=np.nan) for x, y in data if len(x)]
    else:
        interpol = [np.interp(xArr, x, y,
                              left=np.nan, right=np.nan) for x, y in data if len(x)]
    return xArr, interpol