1.191 FAQ-892 How to plot evenly spaced column/bar for unevenly spaced numeric X?

Last Update: 5/14/2021

If you have numeric X and select one Y column to plot column/bar chart

If you were to select B(Y) in the following worksheet and create a column plot (Plot > Basic 2D: Column), the default would be to create the graph shown to the right of the worksheet. This happens because Y values are plotted on a numeric X scale.

Show As Evenly Spaced Bar 1Y.png

If, on the other hand, you had wanted to plot the bars as evenly spaced on the X axis, there are a couple of options:

Show As Evenly Spaced Bar 1Y B.png


Plot by X Column Value:

Setting the X column as Categorical will treat the X values as categories rather than numbers.

Show As Evenly Spaced Bar 05.png
  1. Highlight and right-click on the X column and choose Set As: Categorical.
  2. Highlight Y column to plot a column/bar graph.
Notes:
  • !!!Drawback: Since the X column Format is changed to Text, you will not be able to use it as numeric data for subsequent analysis such as curve fitting.
  • If you want to reorder the categorical values, double click on the Categorical cell and then change the order in the Categories dialog.
Show As Evenly Spaced Bar 07.png
  • In Origin 2017 or earlier versions, column/bar chart always plots column/bars at numeric X location no matter you choose one or more Y columns. So if you have non-evenly spaced X values and want to plot them as evenly spaced columns/bars, you can follow the above method.


Plot by Row Number:

Rather than use X column values, this method plots against row number.

  1. Without selecting any worksheet data, click Plot > Basic 2D: Column and designate X and Y as shown below. If you do not see the <autoX> option under Column, right-click in the right panel and click on Allow Row# as X.
  2. Click OK.
FAQ-892 plot setup.png

You can display the X values at each tick by double-clicking on X-axis labels, then setting Type = Text from dataset and from the Dataset Name drop-down, choosing the X dataset.

FAQ-892 text from dataset.png

If you have numeric X and select multiple Y columns to plot column/bar chart

In Origin 2018 and later, Columns/Bars are plotted with evenly spaced X by default.

Show As Evenly Spaced Bar.png

This is done by setting X tick labels as Text from X dataset.

Show As Evenly Spaced Bar axis 1.png
Notes:

If you want to show Columns/Bars at their actual numeric X locations, there are two approaches:

  1. Double-click on any X tick label to open Axis dialog.
  2. On the Tick Labels tab, set Display> Type as Numeric. Click OK.
    Show As Evenly Spaced Bar axis 2.png
  3. Click the Rescale button Rescale button.png to show the full scale range.


Alternately

  1. Select Preferences: System Variables... menu.
  2. Set system variable @DRX as 0. See this FAQ for information on setting the value of a system variable.

A note on plotting date-time data

Prior to Origin 2021b, date-time values in the X column would be treated as Text from dataset when labeling the X axis. This doesn't produce a true date-time scale.

This is changed and now date-time values in the X column will be treated as Date when labeling the X axis of the Column/Bar plot.

FAQ-892 Date time X.png

Keywords:unevenly spaced, column, bar, evenly spaced, equally spaced, isometric, discrete, date, time
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