Information Technology Reference
In-Depth Information
hand. For example, if the titles of a collection of publications are to be displayed,
then it is more appropriate to display these as an ordered list rather than as
the sorts of tag clouds one typically sees where several tags are displayed in a
single line. We therefore provide a set of basic visualisation types, illustrated in
Figure 3, from which a developer may choose. We will describe each of these
working from left to right.
Corsin Decurtins
Matthias Geel
Adriana Ispas
Stefania Leone
Fabrice Matulic
Michael Nebeling
Moira Norrie
Alexandre de Spindler
Tilmann Zaeschke
Christoph Zimmerli
Adriana Ispas
Alexandre
de Spindler
Christoph Zimmerli
Corsin Decurtins
Fabrice
Matulic Matthias Geel
Michael
Nebeling
Moira Norrie
Stefania Leone
Tilmann Zaeschke
Fig. 3.
Visualisation modes for authors
The first visualisation is a simple list of author names, sorted alphabetically
by surname and with no variable visual features. The second visualisation is
a tag cloud where the tags are aligned horizontally, sorted alphabetically by
forename, and their size indicates the number of publications of the author. We
refer to this as a line-based visualisation. The third visualisation is similar to
ones produced by tools such as Wordle
5
where an advanced algorithm is used
to align tags with aesthetics in mind and it can also be used to visualise various
forms of relationships between tags. We refer to this as a spiral visualisation
since the tag cloud is formed working from a central point and then positioning
tags around that point while moving outwards. The fourth visualisation shows
that we also support non-textual tags such as images. Any of the three basic
visualisation types—list, line-based and spiral—can be used with both textual
and non-textual tags.
4 Model and Specification
Our approach builds on the model of a browser that can define multiple syn-
chronised tag clouds to visualise the data stored in one or more data collections.
The application developer can configure such a
browser
as a search interface
through an augmented data model that specifies the
viewer
classes, their asso-
ciated
views
in the form of tag clouds and the
visualisations
of these tag clouds.
Figure 4 illustrates this concept and how it extends the data model stored in
a relational database with a view model based on the shared concept of views.
Note that we use the relational model and later SQL, since the majority of web
sites build on relational database systems, such as MySQL, for the storage and
retrieval of data. However, we note critically that our approach is based on gen-
eral database principles, such as data tuples and views, and is therefore not tied
to a particular database system or modelling language.
5
http://www.wordle.net
