Re: experimental support for SPV files now available

[Ben Pfaff]

On Tue, Nov 27, 2018 at 11:46:59AM -0600, Alan Mead wrote:
> On 11/27/2018 10:34 AM, Ben Pfaff wrote:
> > New .spo files do show up regularly at the converter webpage.  That's
> > how I collected most of my 3000+ .spv files, too.  (I'd have far more
> > .spo files if I hadn't inadvertently deleted most of them a few months
> > ago not recognizing the format.)
> 
> I take it that SPO and SPV files are very different?

They're very different on the outside--an SPV file is a Zip archive and
an SPO file is a MS Compound Document Format archive.  I haven't looked
enough at what's inside an SPO file yet to say how different the
contents are, but I suspect that they are very different.

> How "smart" are SPV files? I ask because I've had the experience of
> opening an SPV file in SPSS and SPSS seems to be composing the results
> (a table or a chart). I had the impression that it was re-running the
> analysis, but maybe that's a poor assumption. 

SPV files contain results, in the form of pivot tables, charts, and
other objects.  Loading one does not re-run analyses, but it does load
objects from disk only as they come into view, and it does take a little
bit of CPU to display them.

> But I believe I've heard reports that when people with different
> licenses exchange SPV files, some results cannot be displayed (because
> a particular module is not available on the viewer's SPSS license). 

I guess that SPSS could limit what it shows however it likes, but the
pivot tables in SPV files are generic.  A program that can display any
SPV pivot table should be able to display all of them.

Some SPV files contain a specialized kind of object called a "model".  I
don't know anything about these yet.  It is possible that displaying
models requires a special license.

Some SPV files produced by a newer version of SPSS might not display on
older versions.  I've tried to implement all the features that appear in
the corpus, which includes files produced by newer and older versions of
SPSS.

> If so, I imagine there are limits on what PSPP can do to display some
> SPO files?

SPO files are a separate question.  I don't know if they have the same
underlying data model as SPV files.  If not, they might be hard to deal
with.  I need to investigate the ones I have before I can guess.  But
I'm planning to get SPV files fine-tuned before I look at them.