Visualisation Reference Framework Mark Nixon, Martin Taylor, Margaret Varga, Jan Terje Bjørke and Amy Vanderbilt

IST Reference Model

Summary of Data Types Acquisition Streamed regular sporadic Static Sources Single Multiple Choice User-selected Externally imposed Identification Located Labelled Values Analogue scalar vector Categoric (classic) symbolic linguistic non-linguistic non-symbolic linguistic non-linguistic Categoric (fuzzy) symbolic (non-linguistic) non-symbolic (non-linguistic) Interrelations User-structured Source-structured

Summary of Display Types Display Timing static dynamic Data Selection User-selected Algorithmically directed Data Placement Located Labelled Data Values Analogue scalar vector Categoric linguistic non-linguistic

Some examples of mapping data types onto display types Data typeDisplay typeComment Streamed DynamicThe user ordinarily wants to act when some event occurs Located 2-D or 3-D Located The display is a 2-D or 3-D map of some attribute(s) of the data. If the location identification of the data are in higher dimensional spaces, there is no such natural mapping. Tricks must be used. Labelled The display is likely to be tabular, or some kind of a graph such as a histogram or pie chart Analogue scalar Even if the data are identified by label, its analogue values map naturally to analogue display variables such as the length of a line or the brightness of a pixel. Analogue vector 2-D A 2-D attribute can be mapped onto an area display, a line with length and orientation, a colour hue, a sound location, a sound intensity and pitch, and so forth, all analogue vector attributes of the display. 3-D,A 3-D attribute can similarly be mapped into a volumetric display. Analogue vector Higher dimensional analogue attributes can be displayed, but the mapping is less obviously "natural." Categoric Categoric data values have no natural relation to analogue display values, and must be displayed categorically. The categoric display attributes may or may not map "naturally" ont the categoric data attributes. This kind of mapping is usually considered to be "cognitive metaphor."

Global Attributes of Networks Relevant to Visualisation Topology –Connectivity –Links & nodes –Symmetries –Boundaries –Hierarchical –Tree –Topology evolution in time and space –Embedding space Located/partially located/un-located –Multipartite –Cyclicity –Minimum spanning tree –Closures Reflexive-transitive closure (ancestral) –Hyperstructure Constraints –Rules Thresholds and changes Metrical properties –Path length –Diameter –Density Traffic –Flow –Path –Routing Logical/physical Redundancy Open/Closed Layers Overlapping – partial, complete –Relationships

Local Attributes of Networks Relevant to Visualisation Nodes –Node ID –Location –Node type –Weight Fuzzy Probabilistic –Open/Closed –Input/output property –Memory –Constraints & rules –Informational properties Threshold Links –Link ID –Location –Capacity –Weight Fuzzy Probabilistic –Strength –Direction –Availability –Type of traffic, e.g. protocols –Route –The medium –Memory –Constraints & rules –Informational properties

Representational Attributes of Networks Shape properties Layout Susceptibility to aggregation Duality ……

Attributes of Representations Symbology Visual separation Colour coding Layout Preservation of reference …….

Way Forward Network Visualisation Test Examples –Illustrate the framework –Reveal the missing components –Identify redundancies –Reveal conflicts Develop collaboration environment –WIKI –Bulletin board Integrate the VisTG model, data types and display types in the context of networks