Extending the GGobi pipeline with rggobi
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The recently redesigned GGobi pipeline is a set of interconnected
modules called stages. Clients may create custom GGobi visualizations
by changing the modular composition of the pipeline. For example, the
ggvis plugin extends the pipeline to perform multi-dimensional scaling
on a dataset. The implementation of the pipeline is based on the
GObject system from the GTK+ project.

rggobi, a link from R to GGobi, gives R complete control over the
GGobi pipeline. Besides support for constructing a pipeline from
existing stages, rggobi enables the implementation of new pipeline
stages in R. The R programmer need only provide a set of R callbacks
that satisfies the contract for a stage implementation. Despite the
performance trade-off, R is a convenient platform for the rapid
prototyping of visualizations, because of its high-level nature and
strong support for data analysis. rggobi users may customize
interactive multivariate visualizations on-the-fly in support of an
analysis. This functionality is based on a new RGtk2 feature that
allows the extension of any GObject class from R. As an example, we
extend GGobi to support interactive graph layout based on a system
implemented in R.


Michael Lawrence