Date: Tue, 2 Dec 2008 10:02:53 -0600
Reply-To: "Peck, Jon" <peck@spss.com>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: "Peck, Jon" <peck@spss.com>
Subject: Re: Programmatic manipulation of charts?
In-Reply-To: A<000c01c95492$cb69b270$623d1750$@com>
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To elaborate a bit further, it is possible to manipulate the labels programmatically, but it will take more than two lines of code.
The chart is represented internally as an XML specification, and there are apis in the Python SpssClient module, GetXML and SetXML that allow you to read and change it. The schema is installed with SPSS. So you could write a program to read and parse the XML and manipulate the labels. If you do File>Export Chart XML from the Chart Editor, you can see what it looks like.
Then, for example, you could programmatically remove labels for categories below some threshold value, remove fractional values to use less space, reduce point sizes, or make other changes that might help the layout.
Python has excellent support for manipulating XML - see the ElementTree module if you are interested.
You might find it easier to prepare an XML template using the new VizDesigner product, which gives greater control over details of the charts, and then use that template within SPSS Statistics to generate your charts. You can read about VizDesigner at http://www.spss.com/vizdesigner/
HTH,
Jon Peck
-----Original Message-----
From: SPSSX(r) Discussion [mailto:SPSSX-L@LISTSERV.UGA.EDU] On Behalf Of ViAnn Beadle
Sent: Tuesday, December 02, 2008 8:29 AM
To: SPSSX-L@LISTSERV.UGA.EDU
Subject: Re: [SPSSX-L] Programmatic manipulation of charts?
AFAIK, there is no automatic fitting algorithm for label position. GPL does
allow you to lump really small counts together into a general other
category. The label() function in GPL provides labels for almost anything
you want and can be named multiple times on the ELEMENT statement. But
you'll still have the overlapping problem. The internal representation of
the chart is XML (called vizML). You can export the vizML from the chart
editor and play with it outside of the context of the chart editor. The
GGRAPH command can be used to test rendering within SPSS. SPSS "might" still
license an integrated graphics package based upon the graphics engine used
within SPSS. It is a java based development environment that is used for
direct chart generation and manipulation from data marts and is completely
independent. Talk to SPSS support for more info.
-----Original Message-----
From: Simon Palmer [mailto:Simon.Palmer@strategicdata.com.au]
Sent: Tuesday, December 02, 2008 12:18 AM
To: ViAnn Beadle
Cc: SPSSX-L@LISTSERV.UGA.EDU
Subject: Re: Programmatic manipulation of charts?
Hi ViAnn,
> Both templates and GPL provide "some" control over labels but you'd
> have to
> be more specific as to what you want.
It's data labels in particular that are problematic. I have to
generate a large number of (horrible!) pie charts that need to have
data labels in or near their segments. I have tried templating but it
seems for charts with several little-endorsed values I have to
compromise between not showing all the labels or having them obscure
each other. Templating doesn't seem apply to label padding either, but
that is a minor concern. I can't see anything in GPL that lets me do
anything with data labels, let alone algorithmically specify co-
ordinates that can be set dynamically. On the other hand it looks like
there has been a substantial amount of thought behind the GPL so it
wouldn't surprise me if it was just a lack of understanding on my part.
What I thought might be possible was post-processing of the chart
object, presumably with python scripting. My rough plan was to write
a script that turned on the labels for the pie chart then looped
through a process of checking to see if each data label object
overlapped any other one, and if so keep moving it until it didn't.
But it looks like the only way to manipulate a chart after it has been
produced is via the Chart Editor.
Thanks for your help,
Simon
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