How to extract the values from a bar chart
Reading bar heights off a chart by eye is slow and never quite right. This reads every bar against the axis and gives you the table.
What is read
- Grouped bars: one column per legend entry.
- Stacked bars: each segment's own size, not the running total.
- Horizontal bars, bars on a log axis, and bars with error bars.
- A line drawn over the bars on a second axis.
Steps
- Drop in the chart.
- Check that each bar has its ring at its end.
- Download, or copy the table straight into a spreadsheet.
Printed values
When the chart prints a number on each bar, a picture reading uses the printed number. From a PDF the bar's own height is read, which is the value the chart was drawn from.
Questions
Does it read 3D bar charts?
No. Bars drawn in perspective do not line up with their axis, and no reading of them would be trustworthy.