routine sets a new value for a UNITS component of an existing NDF AXIS
data structure. The NDF
is accessed in update mode and any pre-existing UNITS component is over-written with a new value.
Alternatively, if a ‘null’ value (
) is given for the UNITS parameter, then the NDF’s axis UNITS
component will be erased. If an AXIS structure does not exist, a new one whose centres are pixel
co-ordinates is created.
axunits ndf units dim
DIM = _INTEGER
The axis dimension for which the units is to be modified. There are separate units
for each NDF dimension. The value must lie between 1 and the number of dimensions
of the NDF. This defaults to 1 for a one-dimensional NDF. The suggested default is the
NDF = NDF (Read and Write)
The NDF data structure in which an
axis UNITS component is to be modified.
UNITS = LITERAL (Read)
The value to be
assigned to the NDF’s axis UNITS component (e.g.
). UNITS describes the
physical units of the quantity measured along the axis. This value may later be used by
other applications for labelling graphs and other forms of display where the NDF’s axis
are shown. The suggested default is the current value.
ngc253 "arcsec" 2 Sets the UNITS component of the second axis dimension of the NDF
structure ngc253 to have the value
axunits ndf=spect units=Angstrom Sets the
axis UNITS component of the one-dimensional NDF structure spect to have the value
axunits datafile units=! dim=3 By specifying a null value (
!), this example
erases any previous value of the UNITS component for the third dimension in the NDF