Next: NDF_MSG - Assign the name of an NDF to a message token
Up: FORTRAN ROUTINE DESCRIPTIONS
Previous: NDF_MBND - Match the pixel-index bounds of a pair of NDFs
NDF_MBNDN
- Match the pixel-index bounds of a number of NDFs
- Description:
The routine matches the pixel-index bounds of a number 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_MBNDN( OPTION, N, NDFS, 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.
-
N = INTEGER (Given)
-
Number of NDFs whose pixel-index bounds are to be matched.
-
NDFS( N ) = INTEGER (Given and Returned)
-
Array of identifiers for the NDFs 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
all the NDFs. In effect, the pixel-index bounds of the NDFs are
"maximised" and the "union" of all N sets of pixels is selected.
Any new pixels introduced into an NDF will be padded with the
"bad" value. If the NDFs have different numbers of dimensions,
then the dimensionality of all the returned sections will match
the NDF with the highest 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 all the NDFs. In effect, the
pixel-index bounds of the NDFs are "minimised" and the
"intersection" of all N sets of pixels is selected. An error will
result if the NDFs have no pixels in common. If the NDFs have
different numbers of dimensions, then the dimensionality of all
the returned sections will match the NDF with the lowest
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_MSG - Assign the name of an NDF to a message token
Up: FORTRAN ROUTINE DESCRIPTIONS
Previous: NDF_MBND - Match the pixel-index bounds of a pair 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