Timeline Facets
OpenRefine displays data in a tabular way, much like a spreadsheet. When a project is first loaded, a row is equivalent to a record, and columns represent the types of data within the records, or the variables. Any individual data entry in the interface is called a value, and values are contained in individual cells.
Though the text facet is one of the most commonly used facets in OpenRefine (Text facet counts unique values and displays them, allowing quick and easy correction of data-entry errors), other commonly used ones are Timeline, Scatterplot, and Numeric facets.
We’ll use the Timeline facet on the Treatment Date Column in the sample dataset. First the dates, which have been imported into the project in text format, must be changed to date format. From the Treatment Date column’s drop down arrow, choose Edit Cells – Common transforms – To date. The dates will then convert to an ISO standard date time format, in which times have been appended with all zeroes, as times were not available in the original data. Although this looks messy, it will allow the Timeline facet to work.
From the column’s drop down, choose Facet – Timeline facet and review the resulting chart.
The dates are listed from the beginning to the end of 2019, with the bars representing the frequency of treatments on each date. Use the sliders on either end of the chart to hone in on a range of dates, or even a single date. Notice that the number of rows you’re viewing based on the range of dates you choose adjusts in real time.
