MEAN

        [GREG2\]MEAN [/CLIP Nsigma]

    computes crude statistics on the part of the Regular  Grid  array  lying
    inside  the  current polygon. Blanking values as defined in SET BLANKING
    are ignored. The results are displayed (some of them  according  to  the
    current ANGLEUNIT), and stored in the variables POLY$SUM and POLY$AREA.

    If option /CLIP is present, iterative kappa sigma rejection is  used  to
    reject outlier pixels.