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EXTREMA
[GREG2\]EXTREMA [/BLANKING Bval Eval] [/PLOT] [/COMPUTE]
Computes and shows the minimum and maximum values of the Regular Grid
array: shows XMIN,XMAX,YMIN,YMAX,ZMIN,ZMAX. A useful command for decid-
ing where to set contour levels, or what size to give to the BOX if you
want an exact aspect ratio between two coordinates. The current blanking
value is used, but can be overridden using option /BLANKING.
Option /PLOT specifies that instead of computing global extrema LOCAL
extrema values should be computed, and written at appropriate places on
the plot. This is a very good way to avoid ambiguities in contour map. A
shortest format is used for writing the values, and the character size
controls the label size.
If option /COMPUTE is not present, the extrema are only computed if not
already known (from a previous call to EXTREMA, or from an image head-
er). /COMPUTE forces computation from the data array. It should be used
if for any reason the known extrema are incorrect (invalid image header,
killed bad pixel, change of blanking value...).
Gildas manager
2011-04-01