Hello,

The "Update File Details" button definitely only changes the internal
information, it doesn't go back to the disk again.  And for both Bruker
and Azara formats that would mean having to go back to the header files,
which currently are not even stored.  For the other formats the header is
part of the data file so one could imagine re-opening them.

If the data on disk has changed (say) its number of points in some
dimension then you should be able to change that.  But there are two
"number of points" in the data model.  There is the original number of
points after Fourier transform but before 'extracting' the region of
interest, and there is the number of points in that region, which is the
number of points of the data file on disk.  The latter is specified in the
"Edit Spectrum File Details" dialog.  The former is specified in the "Edit
Spectrum Referencing" dialog.  (For those who don't know, both these
dialogs are reachable from the "Edit Spectrum" dialog, via the buttons at
the bottom.)

In addition, there is a "point offset" column in the "Edit Spectrum
Referencing" dialog.  This is in case your 'extraction' does not start at
point 1.

As an example, say you have 512 points after Fourier transform, and what
to keep only points 301 to 500 inclusive.  (And not that points start at
1, not 0.)  Then the original number of points is 512, the number of
points is 500-301+1=200 and the point offset is 301-1=300.

When you change these values inside Analysis you might get some drawing
errors as the program tries to catch up with the new values.

There is an option in the "Edit Spectrum Referencing" dialog but not the
"Edit File Details" one to keep the peak ppm values the same, rather than
the peak positions.  (I just tried it and it didn't seem to work though,
so I'll have to look into that.)  It sounds like this is the kind of thing
you want.

Wayne

On Mon, 21 May 2007, Patrick van der Wel wrote:

> Hello,
>
> I was wondering if there is currently a work-around for having analysis deal
> with existing spectra in a project that one ends up re-processing. For
> example, changing the zero-filling or in the end deciding to 'extract' the
> region with the peaks from a larger (largely empty?) spectrum (in order to
> save disk space, for instance).
>
> I tried this already a little bit, by re-opening the project, which did not
> work so well. I also tried using the File Details popup from the Spectrum
> listing, along with the Update File Details button. This also did not help.
>
> It would be nice if it were possible to allow something like this, where
> analysis would have to reposition the peaks to the same ppm values and update
> the axis scales etc. (Of course, it is probably tricky to make this
> completely general and fool proof :)
>
> By the way, my guess is that the 'Update File Details' button is mostly to
> manually change some settings within Analysis. It would be nice if the above
> could be implemented as a button that would force analysis to re-read the
> file parameters from disk.
>
> Aside from this, it would already be nice if one could just revert back to the
> original referencing setting from the file, through some command or option.
> (In order to undo operations such as 're-reference to peak' etc)
>
> Patrick
>