figure 1. the n WB tool interface (i) with menu (a), Console (b), Scheduler (c), and Data Manager (d). the two visualizations of Renaissance florentine families used the Guess tool plug-in (ii) and prefuse.org algorithm plug-in (iii) nodes denote families labeled by name; links represent marriage and business relationships among families. in Guess, nodes are size-coded by wealth and color-coded by degree; marriage relationships are in red using the Graph Modifier (d). the “Pazzi” family in (c) was selected to examine properties in the information Window (b).

had more than 66,429 data sets and 35,842 visualizations, while Swivel had 14,622 data sets and 1,949,355 graphs contributed and designed by 12,144 users. Both sites let users share data (not algorithms), generate and save different visualization types, and provide community support. In January 2011, the numbers for Many Eyes increased to 165,124 data sets and 79,115 visualizations, while Swivel ceased to exist.

Data analysis and visualization is
also supported by commercial tools
like Tableau (http://tableausoftware.
com), Spotfire (http://spotfire.tibco.
com), and free tools; see Börner et al. 6
for a review of 20 tools and APIs. While
they offer valuable functionality and
are widely used in research, education,
and industry, none makes it easy for
users to share and bundle their algo-
rithms into custom macroscopes.

Plug-and-Play software
architectures
When discussing software architec-
tures for plug-and-play macroscopes,
it is beneficial to distinguish among:
( 1) the “core architecture” facilitating
the plug-and-play of data sets and algo-
rithms; ( 2) the “dynamic filling” of this
core comprising the actual algorithm,
tool, user interface, and other plug-ins;
( 3) and the bundling of all components
into “custom tools.” To make all three
parts work properly, it is important to
understand who takes ownership of
which ones and what general features
are desirable (see the sidebar “Desir-
able Features and Key Decisions”).