Data viz
Data
Data used for visualization
- Dataset perspective (global)
- Individual data perspective (local)
Structured data
CSV files. 
item = 1 row attribute (feature) = column
Time series data
- Time-series form following the flow of time.
- Audio, video
- Examine trend, seasonality, and cycle over time.
Geographic / map data
- Uses distance, paths, distributions, etc.
Relational data
- Visualizes relationships between objects
- Objects are Nodes
- Relationships are Links
Hierarchical data
- Data with clear containment relationships
- Tree, Treemap, Sunburst, etc..
Types of data
- Numerical
- Continuous: length, weight, temperature..
- Discrete: dice values, number of people…
- Categorical
- Nominal: blood type, religion…
- Ordinal: grade, star rating, rank…
Discrete and ordinal can overlap.
- Discrete: can be used proportionally as numerical values.
- Ordinal: things that are not discrete but have an ordering?
Mark, channel
Mark
- Visualization data composed of points, lines, and areas
Channel
- Elements that can modify each mark 
Pre-attentive Attribute
Elements that people naturally perceive without paying special attention. 
For example, in the figure above, Orientation — you can immediately tell that only the center element has a different tilt.
Using them simultaneously makes them hard to perceive! Use them appropriately to induce visual pop-out.