Dynamic Visualization

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Dynamic Visualization

• Dynamic Queries For Visual Information Seeking by
  Ben Shneiderman
• Data Visualization Sliders by Stephen G. Eick
• Presented by Yimeng Dou
• 05-21-2002
• ydou_at_ics.uci.edu

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Overview

• Dynamic Queries
• Applies the principles of direct manipulation to
  the database environment
• Data Visualization Sliders

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Dynamic Query Approach

• rapid, animated, visual display of search
  results

• Visual presentation of the querys components
• Visual presentation of results
• Rapid, incremental and reversible control
• Immediate and continuous feedback
• No need to learn a specific query language to use
  dynamic query.

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Example 1 HomeFinder System
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HomeFinder

• Christopher Williamson's HomeFinder showed a map
  of Washington, DC and 1100 points of light
  indicating homes for sale.
• Users could mark the workplace for both members
  of a couple and then adjust sliders to select
  circular areas of varying radii.
• Other sliders selected number of bedrooms and
  cost, with buttons for air conditioning, garage,
  etc. Controlled experiments with benchmark tasks
  showed dramatic speed-ups in performance and high
  subjective satisfaction.

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An Improvement To HomeFinder

• ProgramFinder plots the available programs on a
  map of Maryland.
• Adjusting the controls updates the display which
  shows a dot for each program that matches. A
  click on a program provides more details and the
  press of a button generates the paperwork.

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Example 2 Cancer Rate

• (Cervix cancer rates are color coded on the map.
  The year slider shows time trends. )
• The other sliders allow interactive filtering of
  the gap according to the three chosen demographic
  parameters.

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Example 3 Periodic Table

• Periodic table with chemical symbols in red and
  six sliders for attributes such as atomic radius,
  ionization energy, and electronegativity.
• As users move the sliders, the chemical symbols
  change to red showing the clusters, jumps, and
  gaps that chemists find fascinating.
• A study with 18 chemistry students showed faster
  performance with use of a visual display (versus
  a simple textual list) and a visual input device
  (versus a form fillin box).

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Example 3 Periodic Table
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Example 4 Tabular Display

• When there are no natural graphical displays for
  the output, dynamic queries can still be
  implemented with result sets shown in a
  traditional alphanumeric tabular display.
• The sliders and buttons are created
  semi-automatically by the program depending on
  the values that exist in the imported ASCII
  database.
• Display is updated only when the user releases
  the mouse button.

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Tabular Display
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Example 5 Dynamic Query of Unix Directory

• Sliders for size (in kilobytes) and age (in days)
  of files enabled 18 users to answer ten questions
  such as "How many files are younger than
  umcp_tai?"
• The three versions of the program are
• highlighting matches with color
• highlighting matches with asterisks
• displaying only the matching lines
• In five of the tasks there was a statistically
  significant speed advantage for the
  Expand/contract interface.

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Example 5 Dynamic Query of Unix Directory
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Advantages

• Visual presentation of query components
• Visual presentation of results
• Rapid, incremental and reversible actions
• Selection by pointing (not typing)
• Immediate and continuous feedback
• For data in which there is a known relationship
  among variables, the dynamic queries interface is
  useful for training and education by exploration.
• Where there is so much data, dynamic queries may
  help users to discover patterns, form and test
  hypotheses

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Disadvantages
stem largely from their poor match with current
hardware and software systems

• Requirement for rapid performance in search
  algorithms and display strategies cannot be
  easily satisfied with current database management
  tools.
• Application specific programming is needed to
  take the best advantage of dynamic query methods.
• Current dynamic queries implement only simple
  queries that are conjunctions of disjunctions,
  plus range queries on numeric values.
• Visually handicapped and blind users will have a
  more difficult time with these widgets and
  outputs

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Research Directions (1)--Database and display
algorithms

• For small database (main memory) array indexing,
  grid structures, quad trees and k-d trees.
• Larger database (disk) R-trees, grid files,
  various B-trees.
• Display algorithms which can update quickly.
  (Buckets adjusted to granularity of the slider)
• Data compression methods
• Screen management algorithms
• Only repaint the area that is changed
• Manipulation of the palette by color indexing can
  be effective for irregularly shaped regions

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Research Directions (2)--User Interface Design

• Use pictures and capitalize on the human visual
  system.
• Appropriate coding of properties like size,
  position, shape and color, to reduce explicit
  selection.
• Graphical display properties such as color
• Auditory properties.
• No natural two-dimensional representation of the
  data is in currently available widgets.

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Needed New Widgets

• Existing widgets are poorly matched with the
  needs of expert users. One possible solution two
  dimensional input widgets. (Only one selecting is
  required to set two values, correct selections
  can be guaranteed).
• Three and higher dimensional input widget may
  facilitate the exploration of complex
  relationships. One possibility 3-D Mouse.
• Ways of specifying alphanumeric fields. One
  possible solution alphaslider.
• How to specify complex boolean combinations of
  attributes. Example filter/flow model.

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Filter/Flow model

• Users can select from the set of attributes and
  get an appropriate filter widget
• (type-in for interest areas, sliders for cost,
  and buttons for scholarships)
• The widget is placed on the screen with flow
  lines showing ANDs (sequential flow) and ORs
  (parallel flows).

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Summary

• The challenge now is to broaden the spectrum of
  applications by
• improved user interface design
• fast database search
• compression methods
• It can become a general approach attached to
  every database system, spreadsheet, etc.
• Research directions include
• (1) database and display algorithms
• (2) user interface design.

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Data Visualization Sliders

• Sliders provide a threshold bar within a scale
  that user can manipulate with a mouse to select a
  value.
• The effectiveness of sliders may be increased by
  using the space inside the sliders as
• An interactive color scale
• A barplot for discrete data
• A density plot for continuous data

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Sliders in Information Visualization

• Double-edged slider with upper and lower
  thresholds on network maps.
• Categorical slider on software display for
  selecting an arbitrary subset. (see next slide
  for an example)
• Ahlberg and Shneidermans FilmFinder uses a suite
  of double-edged sliders.

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Seesoft (Example of categorical slider)
Lines corresponding to service-affecting messages
(asserts, audits, peripheral interrupts, and
prms) are shown using different colors (gray
levels).
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Filtering

• Its the idea underlying these applications.
• Sliders are used to restrict the information
  portrayed on the screen, thereby pruning the
  visual clutter and enabling the analyst to see
  important underlying patterns.

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Example Frost
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Improvements Upon Traditional Sliders

• The space inside the slider is used as a color
  scale, thereby efficiently utilizing screen real
  estate.
• The data values are shown as tick marks in a rug
  plot in versions A and B and as the bar lengths
  in version D.
• The distribution of the data is shown as a
  density plot in version B and as the bar lengths
  in version D.
• Selected or turned-on, regions are shown in
  colors and unselected or turned-off regions are
  in dark gray. (Similar to operating a paint
  program)

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Summary Of Important Ideas

• Enabling a user to specify an arbitrary number of
  disconnected intervals while preserving the
  intuitive slider interface.
• Using the space inside the slider as a color
  scale.
• Interactively rebinding the colors either to the
  active bars or adjusting the color divisions.
• Presenting the distribution of the data.
• Showing individual data values, either as tick
  marks or as bar lengths.
• Moving between the representations under user
  control, enabling the users to explore from
  several perspectives.
• Linking sliders to the data they control suggests
  many natural and obvious extensions.