1 SIMS 247: Information Visualization and Presentation Software Architectures for Information Visualization Oct 17, 2005

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SIMS 247: Information Visualization and Presentation

Software Architectures for Information VisualizationOct 17, 2005

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infovis history

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interactive tasks [Shneiderman]

• Overview– Get an overview of the collection

• Zoom– Zoom in on items of interest

• Filter– Remove uninteresting items

• Details on demand– Select items and get details

• Relate– View relationships between items

• History– Keep a history of actions for undo, replay, refinement

• Extract– Make subcollections

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software architectures for infovis

• what tools should be provided? – (in-class brainstorm)

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overview

• modeling visualizations• existing infrastructures• platform demos

– processing– prefuse

• administrivia

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infovis reference model

• Data Transformations– Mapping raw data into an organization fit for visualization

• Visual Mappings– Encoding abstract data into a visual representation

• View Transformations– Changing the view or perspective onto the visual representation

• User interaction can feed back into any level

Raw Data

Data Tables

Visual Structures

Views

Data Visual Form

Data Transformations

Visual Mappings

View Transformations

Task

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reference model examples

• Visual mappings– Layout (assigning x,y position)– Size, Shape, Color, Font, etc…

• View Transformations– Navigation: Panning and Zooming– Animation– Visual Distortion (e.g., fisheye lens)

RawData

DataTables

VisualStructures

Views

Data Visual Form

DataTransformations

VisualMappings

ViewTransformations

Task

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apply the model: cone trees• Raw Data: File system directories

– Data Transformations: Traverse file system subtree

• Data Tables: Parsed/extracted directory tree– Visual Mappings: Assign 3D coordinates to tree elements

(layout), assign colors, fonts. Set lighting.

• Visual Structures: 3D model of tree– View Transformations: Camera placement; animation

between tree configurations

• View: Rendered, interactive visualization• Interaction: Selection of new focus node

RawData

DataTables

VisualStructures

Views

Data Visual Form

DataTransformations

VisualMappings

ViewTransformations

Task

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overview

• modeling visualizations• existing infrastructures• platform demos

– processing– prefuse

• administrivia

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building from scratch

• graphics / rendering interface– drawLine, drawRect, drawText, drawImage– transformations (e.g., scale transform for zooming)

• interaction system– callbacks to process mouse and keyboard events

• data and geometry representations– how is the data modeled and manipulated?– how are visual items modeled?

• many different approaches available for facilitating these aspects

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Common Platforms

• flash– 2D Vector Graphics engine– Supports drawing, animation, transforms– Available on most people’s computers– More advanced work by coding in ActionScript– Supports data loading from network using XML

• HTML/CSS/Javascript (AJAX)– Runs right in the web browser– Somewhat messy programming model– For visualization, issues with scale– Difficult to implement advanced visual applications

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processing [Fry & Reas]• a simplified java-based graphics library

– simplifies programming of 2D + 3D graphics– intended to lower threshold for programming visual

applications– includes an integrated development environment using a

sketchbook metaphor, exports to applets– active user community, many extensions and examples

are available online• connection to infovis

– does not currently support infovis with any high-level abstractions

– very useful for prototyping ideas, or as an underlying graphics platform

• http://processing.org

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thinkingmachine 4

martinwattenberg

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existing toolkitsinformation visualizer

jazz / piccolo infovis toolkit

graphviz / jung / pajek

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a hierarchical approach

Visualization• Layout• Render

New Visualization• Layout (override)

• widget hierarchies• extension by subclassing• typing is static• often can’t decompose

visualizations into compositions of basic techniques

• monolithic toolkits– those that primarily use

compile-time inheritance to extend functionality

– [Bederson et al]

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a compositional approach

• Chain together desired components• Extend/replace techniques directly• Directly add new components (or lists of components) to customize

visualizations• Enables dynamic changes in composition• polylithic toolkits

– those that primarily use run-time composition to extend functionality [Bederson et al]

Layout Color Size Render

Visualization

+ + +

New LayoutOther Layout

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design trade-offs

• hierarchical model cited as easier for programmers– fits existing programming models well– less code for common cases

• compositional model provides more flexibility and dynamic behavior– easier to add and extend behaviors– vital for prototyping novel visualizations

• what are the implications for systems by which non-programmers could build visualizations?

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Piccolo• user interface toolkit for zoomable interfaces

– Descended from Pad, Pad++, Jazz– Extensible 2D Visual Objects (text,shapes,images)– Support for Zooming and Animation– Versions for Java, C#, and Pocket C#

• connection to infovis– very popular and robust platform for building your

“geometry” and view tiers.– does not provide high-level visualization abstractions

• http://www.cs.umd.edu/hcil/piccolo

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Authoring Piccolo Applications

• structure visual items in a scenegraph

• create custom visual items through compositing or subclassing existing items

• write interaction code (e.g., mouse listeners)

QuickTime™ and aTIFF (LZW) decompressor

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QuickTime™ and aTIFF (LZW) decompressor


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spacetree

datelens

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infovis toolkit [Fekete04]• extensible collection of infovis ‘widgets’

– scatterplot, treemaps, graph visualizations, etc

• unified data model, similar to database• general interactive components

– dynamic queries, distortion lenses, excentric label

• missing a dedicated “geometry” tier– underlying data and visual abstraction interleaved

• http://infovis.sourceforge.net

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prefuse• User interface toolkit for writing highly interactive infovis

applications (in Java)• Supports node-link diagrams, containment diagrams,

collections, scatterplots, timelines…

• Fine-grained component-based design, rooted in theoretical model for infovis

• http://prefuse.sourceforge.net

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degree-of-interest trees

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vizster

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infovis reference model

Abstract Data Visual Analogues

filtering

Display

DATA VISUAL FORM

User

renderingVIEW

• Separation of data and visual items– Enables filtering and transformation

• Separation of visual items and rendering– Enables dynamic control of appearance (e.g., semantic zooming) and graphics

transforms• User interaction can feed back into any level

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Filter Layout Color Size

Abstract DataNodes, Edges

Visual AnaloguesVisualItems in ItemRegistry

filtering

DisplayInteractive Display

Renderers ActionList RendererFactory

DATA VISUAL FORM

I/O Libraries UI Controls

User

renderingVIEW

prefuse implementation

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filtering



DATA VISUAL FORM

I/O Libraries

UI Controls

User

renderingVIEW

prefuse implementationData structures for structured

(graphs, trees) and unstructured data

Readers and Writers for data I/O

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filtering



DATA VISUAL FORM


User

renderingVIEW

prefuse implementationAn ItemRegistry manages all visual items,maintains caches and rendering queues.

Composable lists of Actions perform data processing:filtering, layout, color, size, font, etc. ActionLists arerun in sequence by a generalized ActivityManager.

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filtering



DATA VISUAL FORM


User

renderingVIEW

prefuse implementationDisplays present the visualization and support interface callbacks and graphics transforms (e.g., pan and zoom).

A RendererFactory assigns Renderers to visualitems for drawing and bounds calculation.

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filtering



DATA VISUAL FORM


User

renderingVIEW

prefuse implementationThe user (possibly you).

User interface controls allow direct interaction withvisualizations (e.g., dragging, brushing, focus selection)

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Filters - graph, tree, fisheyes, …

Assignment - color, size, font, …

Layout - random,circle, treemap,outline, radial,force-directed…

Distortion - bifocal, graphical fisheye

Animators - linear location, polar location, color, font, size

prefuse library components

ActionsRenderers

Controls• Focus, Drag, Select• Highlight, Pan, Zoom

Extras• Physics simulation• Integrated search• Event logging and playback

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evaluation - usability study• qualitative usability study of the prefuse API• 8 participants

– 4 compsci students (2 grad, 2 undergrad)– 3 professional programmers / ui designers– 1 infovis expert

• 3 tasks, given a network dataset:– Create a static visualization with random layout– Apply layout and some form of color mapping– Add animation or interactivity

• study experience– 20 minute tutorial, read through reference handout and perform

code walkthrough of a demo– 1 hour to work on tasks using think-aloud protocol, sessions were

video-taped– post-study interview, audio-recorded

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usability study - results

• 7/8 completed every task– Overall reactions highly positive

• Issues uncovered– Difficulties with filters + data transformation– Misleading naming conventions

• General observations– Copy-and-paste bricolage– Minimal use of provided documentation

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future directions

• refinement of existing models– integration of advanced data modeling with

visualization architecture– richer component libraries– visualization “export” features– (all have been developed in different projects)

• tools for non-programmers– declarative construction of visualizations– Spotfire, Tableau, and others allow this at one level– how best to extend to richer, more nuanced design?

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administrivia

• Any issues with Assignment 2?• Next assignment (project proposal) is online.• Please send in your Tableau histories!

• Next time: begin section on visualizing specific data types. First up: temporal data.

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building a visualization

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building a visualization// create graph and registryGraph g = new XMLGraphReader().loadGraph(datafile);ItemRegistry registry = new ItemRegistry(g); // intialize renderersRenderer nodeR = new TextItemRenderer();Renderer edgeR = new DefaultEdgeRenderer();registry.setRendererFactory( new DefaultRendererFactory(nodeR, edgeR)); // initialize action listsActionList layout = new ActionList(registry);layout.add(new TreeFilter(true));layout.add(new RadialTreeLayout());layout.add(new ColorFunction()); ActionList animate = new ActionList(registry,1500);animate.setPacingFunction(new SlowInSlowOutPacer());animate.add(new PolarLocationAnimator());animate.add(new ColorAnimator());animate.add(new RepaintAction());animate.alwaysRunAfter(layout); // initialize displayDisplay disp = new Display(registry);disp.setSize(500,500);disp.addControlListener(new DragControl());disp.addControlListener(new FocusControl(layout));

// initialize enclosing window frameJFrame frame = new JFrame("prefuse example");frame.getContentPane().add(disp);frame.pack(); frame.setVisible(true); // run the layout listlayout.runNow();

initialize data

set renderers

filter, layout, color

animated transitions

initialize display

add display to window

start it running

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extending a visualization

ForceSimulator fsim = new ForceSimulator();fsim.addForce(new NBodyForce(-0.1f, 15f, 0.9f));fsim.addForce(new DragForce()); ActionList forces = new ActionList(registry, 1000);forces.add(new ForceDirectedLayout(fsim, true));forces.add(new RepaintAction());forces.alwaysRunAfter(animate); add force-based jitter

add overview, pan, and zoom

Display overview = new Display(registry);overview.setBorder( BorderFactory.createLineBorder(Color.BLACK, 1));overview.setSize(50,50);overview.zoom(new Point2D.Float(0,0),0.1);display.add(overview);display.addControlListener(new PanControl());display.addControlListener(new ZoomControl());

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selected applications

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Documents

1 SIMS 247: Information Visualization and Presentation Software Architectures for Information Visualization Oct 17, 2005