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NDF_MBND
- Match the pixel-index bounds of a pair of NDFs
- Description:
The routine matches the pixel-index bounds of a pair of NDFs so
that their array components may be compared pixel-for-pixel
during subsequent processing. Matching is performed by selecting
an appropriate section from each NDF, the method used to define
this section being determined by the value given for the OPTION
argument.
- Invocation:
CALL NDF_MBND( OPTION, INDF1, INDF2, STATUS )
- Arguments:
-
OPTION = CHARACTER * ( * ) (Given)
-
This argument determines how the section to be selected from
each NDF is defined: 'PAD' or 'TRIM' (see the Notes section
for details). Its value may be abbreviated to 3 characters.
-
INDF1 = INTEGER (Given and Returned)
-
Identifier for the first NDF whose pixel-index bounds are to
be matched.
-
INDF2 = INTEGER (Given and Returned)
-
Identifier for the second NDF to be matched.
-
STATUS = INTEGER (Given and Returned)
-
The global status.
- Notes:
-
If OPTION='PAD' is specified, then the NDF bounds will be
matched by "padding"; i.e. each NDF will be extended by selecting
the smallest section from it which encompasses all the pixels in
both NDFs. In effect, the pixel-index bounds of the two NDFs are
"maximised" and the "union" of the two sets of pixels is
selected. Any new pixels introduced into either NDF will be
padded with the "bad" value. If the NDFs have different numbers
of dimensions, then the dimensionality of both the returned
sections will match the NDF with the higher dimensionality.
-
If OPTION='TRIM' is specified, then the NDF bounds will be
matched by "trimming"; i.e. each NDF will be restricted in extent
by selecting a section from it which encompasses only those
pixels which are present in both NDFs. In effect, the pixel-index
bounds of the two NDFs are "minimised" and the "intersection" of
the two sets of pixels is selected. An error will result if the
two NDFs have no pixels in common. If the NDFs have different
numbers of dimensions, then the dimensionality of both the
returned sections will match the NDF with the lower
dimensionality.
-
Note that the initial NDF identifier values will be annulled
by this routine and replaced with identifiers describing
appropriate new sections from the original NDFs. If access to the
original data is still required, then the initial identifiers may
be cloned with the routine NDF_CLONE before calling this routine.
Next: NDF_MBNDN - Match the pixel-index bounds of a number of NDFs
Up: FORTRAN ROUTINE DESCRIPTIONS
Previous: NDF_MBADN - Merge the bad-pixel flags of the array components of a number of NDFs
Starlink User Note 33
R.F. Warren-Smith
11th January 2000
E-mail:rfws@star.rl.ac.uk
Copyright © 2000 Council for the Central Laboratory of the Research Councils