masks out a region of an NDF by setting pixels to the bad value, or to a specified
constant value. The region to be masked is specified by a file (see Parameter REGION)
that should contain a description of the region in a form readable by the Starlink AST
library (see SUN/211
). Such formats include AST’s own native format and
other formats that can be converted automatically to an AST Region (e.g.
IVOA MOC and
STC-S regions). AST Regions can be created, for instance, using the Starlink ATOOLS
package (a high-level interface to the facilities of the AST library).
CONST = LITERAL (Given)
numerical value to assign to the region, or the string
IN = NDF
The name of the input NDF.
INSIDE = _LOGICAL (Read)
TRUE value is
supplied, the constant value is assigned to the inside of the region. Otherwise, it is
assigned to the outside.
OUT = NDF (Write)
The name of the output NDF.
REGION = FILENAME (Read)
The name of the file containing a description of the
Region. This can be a text file holding a dump of an AST Region (any sub-class
of Region may be supplied–-e.g. Box, Polygon, CmpRegion, Prism, etc.), or
any file that can be converted automatically to an AST Region (for instance
an IVOA MOC in text or FITS format, an IVOA STC-S region in text format). An
NDF may also be supplied, in which case the rectangular boundary of the NDF
is used as the Region. If the axes spanned by the Region are not the same as
those of the current WCS Frame in the input NDF, an attempt will be made to
create an equivalent new Region that does match the current WCS Frame. An error
will be reported if this is not possible.
; ATOOLS: ASTBOX,
ASTCMPREGION, ASTELLIPSE, ASTINTERVAL, ASTPOLYGON.