Visual fitting; generalized extreme value distribution; generalized time scale


A utility developed for the Windows operating system enables easy visual curve fitting of the generalized extreme value distribution (GEV), from a screen display of annual maxima in a Gumbel plot. This gives a useful indication of how positioning of curves passing through the data points may result in similar or different return periods for large events. The utility employs a general risk-based time axis, with the usual return period being a special case option.