Tim,
> Is the AXIS information in an NDF meant to be thought of as a part of the
> WCS information when viewing an NDF as an NDX (in, say, treeview)?
> Currently treeview displays the AXIS information as a separate node that
> implies it is not part of the core NDX specification even though the AXIS
> frame is included in the WCS section as an option.
The "physical" and "logical" view of the axis/wcs info within an NDF
differ. Physically, the WCS component in an NDF does not contain an AXIS
Frame. That is, if you used some HDS tool to extract the WCS component of
the NDF, you would find it did not contain an AXIS Frame. The AXIS Frame
is added into the WCS FrameSet on-the-fly when the NDF_GTWCS function is
called by an application to obtain a pointer to the WCS FrameSet. The
"logical" view however is that the AXIS component is subsumed into the WCS
component, and I guess treeview is more interested in this view. Really,
the AXIS and WCS components give two alternative representations of the
coordinate system info in an NDF, and so one option may be to have an
option in treeview to select which representation is to be displayed.
> I suppose what I'm really suggesting is that the AXIS information should
> not be shown when the NDX view of an NDF is displayed, only when the NDF
> is treated as an NDF.
Not sure I see the distinction here between an NDF and an NDX. Mark???
David
|