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generating a small number of vertex buffers, each containing about 65,000
vertices.
To allow for rapid feedback during interaction, it was necessary to
avoid reconstructing the full geometry on every frame. This mandated
separate geometry for the selected subtree, with animation of shader
parameters used to transition between visual selection states.
WebGL is supported only by a subset of browsers and is unavailable
on some mobile platforms, such as Apple's iOS. It may be desirable to re-
implement these spheres using a more broadly-implemented web graphics
framework, such as HTML5's canvas.
Findings and feedback
Layout efficiency
1. Adjacency effectiveness : For the force-directed graph, the
spherical layout provides a topological wraparound that enables
items that may be highly correlated but otherwise pushed to the
edges in a planar layout, to be located close to each other in a
spherical representation.
Fig. 2.12. Left: 2D planar layout of 200 stocks by correlation. Stocks coloured by
degree of correlation to left-most selected stock (PEG, dashed outline). Close
stocks blue and green (highly correlated), distant stocks orange and red (inversely
correlated); stock near bottom-left (GIS) and bottom-right (EOG) green (highly-
correlated, yet pushed far away, dashed outline). Right: same stocks on (left half
of) SphereCorr. PEG is selected (dashed outline - near top-left), with highly
correlated stocks nearby (cyan and green). Inversely correlated stocks on back and
bottom (red). Correlated stocks GIS and EOG (dashed outline) are now located
close to PEG.
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