Introduction

Overview

Teaching: 5 min
Exercises: 0 min

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.

• Locate helpful resources to learn more about OpenRefine.

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.

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.

Getting help for OpenRefine.

You can find out a lot more about OpenRefine at http://openrefine.org, which has some great introductory videos. These videos and other on OpenRefine can also be found on YouTube, search under ‘OpenRefine’.

There is a Google Group that can answer a lot of beginner questions and problems.

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