REGIONMASK - Applies a mask to a region of an NDF

Description:

This routine 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 within a text file (see Parameter REGION) that should contain a description of the region in the form of an "AST Region". This is the system used by the AST library for describing regions (see SUN/211 or SUN/210). Such text files can, for instance, be created using the Starlink ATOOLS package (a high-level interface to the facilities of the AST library).

Usage:

regionmask in region out

Parameters:

CONST = LITERAL (Given)

The constant numerical value to assign to the region, or the string "Bad". ["Bad"]

IN = NDF (Read)

The name of the input NDF.

INSIDE = _LOGICAL (Read)

If a TRUE value is supplied, the constant value is assigned to the inside of the region. Otherwise, it is assigned to the outside. [TRUE]

OUT = NDF (Write)

The name of the output NDF.

REGION = FILENAME (Read)

The name of the text file containing a text dump of an AST Region. Any sub-class of Region may be supplied (e.g. Box, Polygon, CmpRegion, Prism, etc.). If the axes spanned by this 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.

Examples:

regionmask a1060 galaxies.txt a1060_sky

This copies input NDF a1060 to the output NDF a1060_sky, setting pixels bad if they are contained within the Region specified in text file "galaxies.txt".

Related Applications :

KAPPA: ARDMASK; ATOOLS: ASTBOX, ASTCMPREGION, ASTELLIPSE, ASTINTERVAL, ASTPOLYGON.

Implementation Status:

• This routine correctly processes the WCS, AXIS, DATA, QUALITY, LABEL, TITLE, UNITS, HISTORY, and VARIANCE  components of an NDF data structure and propagates all extensions.

• Processing of bad pixels and automatic quality masking are supported.

• All non-complex numeric data types can be handled.