Week 4 — Some Visualization

IAT 461 / 882 · Data Science for Human-Centered Systems · Summer 2026 · Alireza Karduni

Design Principles

Instructor: Dr. Alireza Karduni · TA: Mehdi Jahani

Slides based on material by Prof. Emily Wall

Tamara Munzner

Rules of Thumb

8 guidelines that make or break visualizations

No unjustified 3D
No unjustified 2D
Eyes beat memory
Resolution over immersion
Overview first, zoom and filter, details on demand
Responsiveness is required
Get it right in black and white
Function first, form next

No Unjustified 3D

The easiest way to make your instructor grumpy about a design

Bad 3D Examples

Magnitude is Effective in Planar Spatial Position (Not 3D!)

We See in 2.05D

Depth Cues

Occlusion Hides Information

3D v. 2D Bars

Why Not 3D?

3D Pie Chart

3D Time Series

Van Wijk 1999

Alternatives? Transform.

Van Wijk 1999

When is 3D Justified?

Benefits outweigh costs
True 3D spatial data
When task is shape perception
Needs very careful justification for abstract data

Li 2007

No Unjustified 2D

Sometimes a simple list is enough

Like… Why Though?

Does a Network Require 2D Layout?

Is reading a central task?
Network → lower info density, harder label lookup (compared to a list)
Benefits > costs when topological structure & context are important

Perer 2008

Sometimes 2D is Helpful

Change over time

Slope graph / bump chart

Eyes Beat Memory

Keep them on the screen

Eyes Beat Memory

External Cognition

Information needed to think is externalized — written down, encoded outside your head
Offloads cognition to perception
Easier to visually compare things side-by-side than to compare a visual to a memory
Small multiples > animation (often)

Small Multiples

Image Composite

Overview First, Zoom & Filter, Details on Demand

Ben Shneiderman’s Information Seeking Mantra

Overview First

Zoom and Filter

Details on Demand

Interactive Example

Responsiveness is Required

For modern accessible visualizations

Visual Feedback

0.1 sec — perceptual processing
- Sub-second response for mouseover highlighting
1 sec — immediate response
- Fast response after mouse click, button press
10 sec — brief tasks
- Bounded response after dialog box — mental model of heavyweight operation (file load)

Considering Scalability

Highlight section without complete redraw of the view (graphics front-buffer)
Show hourglass for multi-second operations (check for cancel / undo)
Show progress bar for long operations (process in background thread)
Rendering speed when item count is large (guaranteed frame rate)

Dynamic Querying

Function First, Form Next

For effective communication

Form vs. Function

Dangerous to start with aesthetics.

Very difficult to add function retroactively.

Masochist’s Teapot

Masochist’s Teapot by Jacques Carelman

Basic Graphic Design Ideas

Proximity — group related items; avoid equal whitespace between unrelated items
Alignment — avoid automatic centering
Repetition — unify by pushing existing consistencies
Contrast — if not identical, make very different

The Non-Designer’s Design Book 2015

Best Practices: Labeling

Meaningful & useful titles, labels, and legends
Axes and panes / sub-windows should have labels
Axes should have good min / max boundary tick marks
Everything that’s plotted should have a legend
Use reasonable numerical format

Get it Right in Black and White

In case of empty color cartridges

Color to Grayscale

Grayscale Test

Viridis Colormap

Viridis in Grayscale

Color Accessibility

Colorblindness Simulation

Perceptually Uniform Colormaps

Edward Tufte

Graphical Excellence

“Graphical excellence is that which gives to the viewer the greatest number of ideas in the shortest time with the least ink in the smallest space.”

— Edward Tufte