Visualizing Tabular Data CS 4390/5390 Data Visualization Shirley Moore, Instructor September 29,

Image Credits All images from Munzner Chapter 7 unless otherwise noted. 2

Tabular Data Large classes of datasets can be characterized in the form of tables. – e.g., relational databases General form is a matrix of key attribute(s) in one or more dimensions and associated value attribute(s) in the remaining dimensions. May have linked tables where value attribute in one table is key attribute in another Layout and visualization of high dimensional tablular data is a challenging vis research problem. 3

Using the Spatial Channel 4

Key vs. Value Attributes Key – Unique index used to look up items in a table – Can be categorical or ordinal Value The value of a cell in a table – Can be categorical, ordinal, or quantitative Design choices for visually encoding a table depend on how many keys and how many attributes it has – Show only values: scatterplot – Show one key and one value: bar chart – Show two keys and one value: heat map – Show many keys and many values: recursively divide subspace into many regions 5

Scatterplot 6

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Scatterplot with Negative Correlation 8 Image credit:

Scatterplot with Log Scaling 9

Bar Chart 10

Pie Chart 11

Bar and Pie Chart Examples Bar chart – Pie chart – D3pie pie chart generator D3pie 12

Stacked Bar Chart 13

Stacked Bar Chart vs. Grouped Bar Chart Stacked bar chart example: – Grouped bar chart example: –

Line Chart 15

Don’t use line chart for categorical data! 16

Time Series Data – Area Chart vs. Lines Chart Exercise: In less than one minute, draw the line showing the sales trend for East from the area chart on the next slide (image from area-chart-vs-line-chart-great.html ): area-chart-vs-line-chart-great.html 17

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East Sales Trend – How close were you? 19

Lines with Total 20

Normalized Stacked Bar Chart 21 Example:

Streamgraph 22 Mathematical algorithms minimize change in slope (“wiggle”) in individual series.

Streamgraph Examples Original paper by Byron and Wattenberg with Listening History example – Movie Box Office Receipts NYTimes article – /movies/ _REVENUE_GRAPHIC.html /movies/ _REVENUE_GRAPHIC.html Article discussing streamgraphs – 08/making-sense-of-streamgraphs/ 08/making-sense-of-streamgraphs/ 23

Heatmap 24

Heatmap with Hierarchical Clustering of Key Attributes 25

Circular Heatmap Example 26

Scatterplot Matrix (SPLOM) 27 D3.js SPLOM example: splom.html

Parallel Coordinates 28

SPLOM vs. Parallel Coordinates 29

Correlation with Parallel Coordinates 30

Parallel Coordinates Examples With brush filtering and reorderable axes – With k-means clustering (from Wikipedia): 31

Preparation for Next Class Read Munzner Chapter 7 Scott Murray’s D3 Tutorial – Bring in interesting high-dimensional tabular datasets (can use for Lab 3) 32