Parallel Coordinates (legacy)

During the 1980’s and early 90’s, Inselberg and Dimsdale (A. Inselberg and B. Dimsdale, "Parallel Coordinates: A Tool for Visualizing Multidimensional Geometry," Proc. IEEE Figure 11. Before and after a focus and context effect is introduced. Visualization 1990, IEEE Computer Society Press, San Francisco, California, USA, October 23-25, 1990, pp. 361-378.) introduced Parallel Coordinates, a representation of multi-dimensional information or data, in which multiple dimensions are allocated one-to-one to an equal number of parallel axes on-screen. An object in a data set is then mapped as a series of points, one per axis, with the position of each point on the axis being dependent on their value in the associated dimension. The points are then joined together by line segments from one axis to its immediate neighbour, forming a poly-line across the set of axes.

Only columns with a valid domain are available in this view. Make sure that the predecessor node is executed or set the domain with the DomainCalculator node!

HiLiting:

The data points may be selected by either dragging a rectangle with the mouse over the points on the parallel axes or by clicking on points or connecting line segments (if curves are drawn, selection works only on the datapoints). Hold control pressed for multiple selections. The selected datapoints may be hilited by either right-click to get the context menu or via the hilite menu in the menu bar.

Tooltip

Move the mouse over the data points on the parallel axis to get information about the RowID and the value.

Properties:

Default Settings:

• Mouse Mode: choose "Selection" to select the datapoints or "Zooming" to zoom in. If you have zoomed in you may choose "Moving" to navigate in the zoomed display. If you want to rearrange the parallel axes choose "Transformation". The axes can then be selected and dragged to another position.
• "Fit to screen" fits the display again to the available space.
• "Background color lets you choose the background color of the display.
• "Anti-aliasing": Check if the view should enable anti-aliasing (make a smoother drawing). This will slow down performance as well.

Column Selection: Choose the columns you want to have displayed as parallel axes.

Missing Values:

• "Skip rows containing missing values": if a row contains a missing value, this row is not displayed (Default)
• "Skip only the missing value" would interrupt the line by leaving out the missing value at the referring parallel axis.
• "Show missing values" draws a horizontal bar at the bottom and maps the missing values to this bar. This provides a quick overview over the existence and distribution of missing values.

Appearance:

• "Show/Hide dots": Check if the points on the parallel axes should be displayed explicitly as dots; uncheck if you want to hide the dots.
• "Draw curves instead of lines": Connects the datapoints not with linear interpolated line segments but with cubic curves. In this way it is easier to see one sample (row) since the continuation of the line after a common data point can easily be seen (see: m. Graham, J.Kennedy: "Using Curves to Enhance Parallel Coordinate Visualizations").