INFORMATION VISUALIZATION ON SPHERES - Information Visualisation: Techniques, Usability and Evaluation - page 31

Fig. 2.9. Implemented SphereCorr with UI and narrative panel.

SphereCorr was implemented as follows:

• Marker Layout : A marker for each entity (e.g. a security) is

placed on a sphere with the layout given by a force directed
algorithm [Kob05] so that most highly correlated items are
attracted to each other and inverse correlations repel.

• Market Attributes : The marker size, colour, and shape are based

on data attributes. Size was set to a measure of volume, colour
initially set to category, and the overall shape was modified with a
notch/needle [Bra10] based on the time series trend: .

• Navigation : Virtual trackball navigation, with click and drag to

turn, and mouse-wheel to zoom.

• Exploration and Selection : Mouse hover for tooltips, click for

selection, second click for drill down to web page. Mouse selection
overrides the categorical colour scheme with a quantitative colour
scheme indicating the degree of correlation to the selected item.

• Additional User Interface Elements : Interactive features include

search, filter, flip viewpoint and auto-rotation (a very slow rotation
that aids perceptual discrimination between foreground and
background).

• Narrative : Explanatory text with buttons forming tacit tutorials is

also included.