Bootstraped analysis of the green line observed on March 7, 2019, as in Figure 2. For the intensity, DoLP and AoLP, we superpose as dotted line the estimated parameters as in Figure 2, to the boxplot (histogram) of the bootstrapped parameters. 1000 realisations have been calculated using a parametric model of Petit Cru. On each realisation, the parameters are reestimated, allowing the statistical analysis displayed. The box contains half of the reestimated parameters (between 25 and 75% percentiles). Red crosses correspond to outliers as decided by the automatic plotting routine. The parameter S/N completes the plot. As can be observed, low values of S/N lead to poor estimates of the angle, and to a higher bias in the DoLP.