How to digitize a time series graph
When the x axis is dates, a digitizer that gives back pixel positions leaves you converting them by hand. Here the dates come back as dates.
What is read
- Axes in days, weeks, months or hours.
- Each point's date, placed between the labelled ticks.
- In the Excel file the dates are real dates.
What we measured
- From PDFs: 300 of 300 charts with a date axis read correctly.
- From pictures: 14 of 15 on a fresh set, after 21 of 25 on the first.
Steps
- Drop in the chart.
- Check the first and the last date in the table against the axis.
- Download Excel or CSV.
Questions
The axis shows only years. Is that a date axis?
Plain years are read as numbers (2019, 2020, ...), which plots the same way.