An NDF section may be created using the routine NDF_SECT. For instance:
INTEGER NDIM, LBND( NDIM ), UBND( NDIM )
...
CALL NDF_SECT( INDF1, NDIM, LBND, UBND, INDF2, STATUS )
will create an NDF section starting from an NDF with identifier INDF1, and will return a new identifier INDF2 which refers to the section. The set of pixels in the original NDF to which the new section should refer is determined by the arguments NDIM, LBND and UBND.
These arguments not only specify the set of original pixels to which
the new section should refer, but also directly determine the
shape (i.e. the pixel-index bounds and the
dimensionality)
of the new section.
For instance, a call to NDF_BOUND using the new identifier INDF2 would
return the same values as had originally been specified in the call to
NDF_SECT.