- There is human in the loop - perception, cognition and culture
- More or less control/interaction - more control means more challenging to learn and difficult to find patterns and comprehend structure of network, less means less discovery through exploration, less analytical process.
- Too much data - Problem with too much data is that it produce clutter, affect cognition, may cause information loss and limits on cognition. How do we display huge amount of information clearly without distorting or hiding information.
- Algorithm - needs to be fast enough
- Evaluating - evaluate in terms of efficiency, how easy it is to learn, does it help make decisions
- Dare I say, make the invisible visible.
Solutions
Solution 1. Human visual processing involves two levels: automatic (Sensory) and controlled processing (arbitrary) works on visual properties such as position and colour[1][2]. It is highly parallel, but limited in power. Controlled processing works on abstract encodings such as text. It has powerful operations, but is limited in capacity. The distinction between these two types of capacity is important for visual design.
Understand Data
Three main categories
- Nominal
- Ordered
- Quantitative
1. Marks
(Point, Line, Area, Surface, Volume)
2. Know your visual channel types and ranks
3. Effects on human perception
- Accuracy (Stevens' psychological power law)
- Discriminability
- Separability vs Integrality
- Dangers of depth
- Data/Ink ratio
- categorical colour constraints
- power of the plane
- resolutions beats immersion
- eyes beat memory
4. Visual encoding - which data best suited for which representation
- Effectiveness principle, encode most important attributes with highest ranked channels [ Mackinlay 86]
Understand design process
Beyond encoding need to understand the problem that you are trying to solve(what to show), abstraction (what to represent), encoding and algorithm and needs validation at each step.
Identify problem
- provide novel capabilities
- speed up existing workflow
Abstraction - abstract from domain specific to generic
- operations => sorting, filtering, browsing, comparing, finding trends/outliers, characterising distributions, finding correlations
Encoding
Algorithm
Solution 2. Use SYFD (Systematic yet flexible discovery?)
http://hcil2.cs.umd.edu/trs/2007-26/2007-26.pdf
Solution 3. Use the visual analytic mantra - Analyse, show the important, zoom/filter analyse further, details on demand.
[1] R. M. Shiffrin and W. Schneider, “Controlled and automatic human information processing: II. Perceptual learning, automatic attending, and a general theory,” Psychological Review, vol. 84, pp. 127–190, 1977.
[2] Edward Tufte - Visual display of quantitative data
