Composing Pages with Charts

Guidelines

• The essential question in data analysis is: "Compared to what"? To understand your data, you need to place it in a context.

• Most interesting problems are essentially multivariate: there are a variety of factors that interact. Include many dimensions of data in your analysis.

• "Follow your data" when you are analyzing by changing the display, the data, or the charts to show you new relationships as you try to understand what you are seeing.

• A design strategy that is often effective is: "Overview first, zoom and filter, then details-on-demand" (HCIL). Provide an overall chart that covers the problem space. You should try to use a multidimensional chart for the overview (e.g., scatter plot, Multiscape, ParaBox, Data Constellations, Map, Time Table). Use filtering and zooming to focus on a subset, then explore that subset by examining its details.

When you are designing a visual display of your data, consider these factors:

• Show as much data as you can: a chart can comfortably accommodate one to two orders of magnitude more data than a spreadsheet can.

• Extract data at the granularity of items that you want to understand. For example, if the raw data is transactions, aggregate to higher level entities (e.g., products, people, relationships).

• First choose charts that directly reflect relationships you are interested in:

  • Characteristics of a field: Bar, Pie, Line Chart, Histogram

  • Interaction of two things: Scatter Plot, Multiscape

  • Subsets over multiple fields: ParaBox

  • Outliers over multiple fields: ParaBox

  • Interactions between multiple fields: Data Sheet, ParaBox

  • Relationships: Data Constellations

  • Events over time: Time Table

  • Geospatial data: Maps

  • Details about data or subsets (often used for the "details on demand"): Data Sheet

• Increase the dimensionality of your analysis by combining multiple charts into a page. Selection and coloring increase the number of dimensions that can be correlated. Filtering provides drill down to focus on a subset. (See Visual Discovery for more details.)

Too many Charts on a Page?

Here are things to try if you find your Page to be unable to fit all of the charts you think you need:

• Reexamine objective of the Page:

  • What questions/problems is it trying to address?

  • Are all charts needed in that Page?

  • Are there other Visuals that might be as good (or better) with less space usage?

• Use multiple Pages

• Use Data Hierarchies

• Orient bars in Bar Charts sideways (except for time-related dimensions)

• Reduce font sizes (especially titles)

• Eliminate titles if redundant w/axes labels

• Align filters in two columns on left and right or along left and bottom

• Use Full Screen button (client tool only)