Parallel Plots (AKA Parallel Coordinate Plots) are a new type of graph available in Origin 2019. They are a somewhat specialized way of plotting multiple dataset-based variables in order to access the relationships between the different variables.
In order to create Parallel Plots in Origin, the variables must be in columnar form similar to the two classic sets of data illustrated below:
You will observe the addition of a “grouping column” at the end of the Fisher’s Iris Data. This column can make assigning color lists easier for some types of Parallel Plots.
Origin 2019 offers three choices in it’s Plot: Parallel Plot menu:
- Parallel Plot: This plot is meant for continuous numeric data. It is the most basic option. Data is drawn with discrete lines and colors are based on color mapping of the one of the columns (though other options are available for plot colors such as color increment lists). The Fisher’s Iris Data illustrated above is a good example of this type of data. (Ignore the “species” column for now.)
- Parallel Sets: This plot is meant for use when all of the variables contain discrete data such as categorical data. Data is drawn with broad strokes whose thickness is dictated by the frequencies of the categories in each variable. The Titanic Survivors data illustrated above is a good example of this type of data. An example of this type of graph is illustrated below.
- Parallel Index: This plot is actually a shortcut to a pre-customized basic Parallel Plot. It expects that the very last selected column will be used to build a color list for grouping individual lines. For example, in the Fisher’s Iris Data illustrated above, the last column (“Species”) would provide the increments for the color list. As well, it would provide the values to put into the legend for the graph. There are a few other preset’s that come with this particular graph, but we will not cover them here. An example of this type of graph is illustrated below.
A few key ideas about Parallel Plots in Origin are:
- You can control curvature and transparency in the Parallel tab of the Plot Details dialog.
- There are no X or Y axes per se. Each variable (column of data) gets it’s own axis which runs vertically.*
- You can specify shared or individual axis scales via the Axis dialog.
- The “Combined Sets” setting in the Plot Details dialog enables completely overlapping data in each sub-panel (area between two axis lines), to be rendered as one unit. Origin determines the colors of these combined sets by mixing the colors of all the individual sources.
I will not explain how to create the above graphs in this blog post. But you can download the zipped Origin project file. It contains the data and instructions necessary to get most of the way there for the two graphs presented above. You’ll have to add your own finishing touches though!!!
*Unless you exchange X-Y axes as I did in the graph illustrated above.