Introduction

Last updated on 2023-07-19 | Edit this page

Estimated time: 10 minutes

Overview

Questions

  • What is OpenRefine useful for?

Objectives

  • Describe OpenRefine’s uses and applications.
  • Differentiate data cleaning from data organization.
  • Experiment with OpenRefine’s user interface.

Motivations for the OpenRefine Lesson

  • Data is often very messy. OpenRefine provides a set of tools to allow you to identify and amend the messy data.
  • It is important to know what you did to your data. Additionally, journals, granting agencies, and other institutions are requiring documentation of the steps you took when working with your data. With OpenRefine, you can capture all actions applied to your raw data and share them with your publication as supplemental material.
  • All actions are easily reversed in OpenRefine.
  • If you save your work it will be to a new file. OpenRefine always uses a copy of your data and does not modify your original dataset.
  • Data cleaning steps often need repeating with multiple files. OpenRefine keeps track of all of your actions and allows them to be applied to different datasets.
  • Some concepts such as clustering algorithms are quite complex, but OpenRefine makes it easy to introduce them, use them, and show their power.

Features

  • Open source (source on GitHub).
  • A large growing community, from novice to expert, ready to help. See Getting Help section below.
  • Works with large-ish datasets (100,000 rows). Can adjust memory allocation to accommodate larger datasets.
  • OpenRefine always keeps your data private on your own computer until you choose to share it. It works by running a small server on your computer and using your web browser to interact with it, but your private data never leaves your computer unless you want it to.

Most functionality does not require an Internet connection and keeps your data within the computer. Some functions, however, like looking up data from URLs or reconciling values in your dataset with online services, necessarily require that data is sent to the online services. While this lesson does not cover these functions, it may be important to know how data could be shared with outside parties, especially if you work with sensitive or confidential data.

Before we get started

Note: this is a Java program that runs on your machine (not in the cloud). It runs inside your browser, but no web connection is needed.

Follow the Setup instructions to install OpenRefine.

If after installation and running OpenRefine, it does not automatically open for you, point your browser at http://127.0.0.1:3333/ or http://localhost:3333 to launch the program.

OpenRefine is used through its graphical user interface in this lesson. In classroom settings or in online classes, you probably want to zoom in on the interface so that text is readable to all. However, when you zoom in, some controls may fall outside the view. Dialog windows in OpenRefine cannot be dragged, so the only way to show buttons that were outside the view is to zoom out again.

If you are planning to teach this lesson to a big room, you may want to check if the main projector screen or monitor is large enough to show all of the user interface while having the text large enough that all learners can see it.

Key Points

  • OpenRefine is a powerful, free, and open source tool that can be used for data cleaning.
  • OpenRefine will automatically track any steps allowing you to backtrack as needed and providing a record of all work done.