22 free tools for data visualization and analysis

Visualization applications and services

These tools offer a number of different visualization options. While some stick to conventional charts and graphs, many offer a range of other choices such as treemaps and word clouds. A few offer geographical mapping as well, although if you're interested in maps, our sections on GIS/mapping focus specifically on that.

Google Fusion Tables

What it does: This is one of the simplest ways I've seen to turn data into a chart or map. You can upload a file in several different formats and then choose how to display it: table, map, heatmap, line chart, bar graph, pie chart, scatter plot, timeline, storyline or motion (animation over time). It's somewhat customizable, allowing you to change map icons and style info windows.

There are some data editing functions within Fusion Tables, although changing more than a few individual cell entries can quickly become tedious. You can also join tables (which is important when the data you want to map is in multiple tables), and filter, sort and add columns and so on. There are also options to allow others to make comments on the data itself.

Mapping goes beyond just placing points, as many of us are accustomed to with Google Maps. Fusion tables can also map multiple polygons with variations in color based on underlying data, such as this intensity map showing the percentage of households with Internet access by state from 2007 U.S. Census bureau data.

The Knight Digital Media Center notes that a handy undocumented feature allows the use of Fusion Table's "templating" export to generate a JSON file from data in other formats. JSON is required by some APIs and JavaScript libraries.

Unlike IBM's Many Eyes, Google lets you designate your data as private or unlisted as well as public, although your data still resides on Google's servers -- a benefit or drawback, depending on whether server bandwidth costs or data privacy is more important to you.

What's cool: Fusion Tables offers relatively quick charting and mapping, including geographic information system (GIS) functions to analyze data by geography. The service also automatically geocodes addresses, which is useful when trying to place numerous points on a map. This is an excellent tool for beginners and advanced beginners to use to get comfortable with analyzing data; it's also a good fit for people who don't program. For more advanced users, there's an API.

Drawbacks: Functionality, customization and data capacity are all limited compared with desktop applications or custom code, and interacting with large data sets on the site can be sluggish. And it has its limitations -- the site choked on March 11, the day of the devastating earthquake and tsunami in Japan. (It is still a Google Labs beta project.)

Skill level: Beginner.

Runs on: Any Web browser.

Learn more: A Google Fusion Tables tour and several tutorials are available. We've also got some examples of what it can do in our story "H-1B Visa Data: Visual and Interactive Tools." Also see the Fusion Tables Example Gallery.

Impure

What it does: Impure is sort of a Yahoo Pipes for data visualization, designed for creating numerous types of highly polished graphical representations of data using a drag-and-drop workspace. The service includes a library of objects and various methods, and -- as with Yahoo Pipes -- it allows you to click and drag to connect modules so that the output of one becomes the input of another. It was developed by Spanish analytics firm Bestiario.

What's cool: Impure offers a highly visual interface for the task of creating visualizations -- which is not as common as you might expect. It has a sleek user interface and numerous modules, including quite a few APIs that are designed to pull data from the Web. It features numerous visualization types that are searchable by keywords like numeric, tables, nodes, geometry and map. And although it saves your workspaces to the Web, you can copy and save the code behind your workspaces locally, so you can back up your work or maintain your own libraries of code snippets.

Drawbacks: Users of Impure face a surprisingly steep learning curve despite its drag-and-drop functionality. The documentation is detailed in some areas, but lacking in others. For instance, while it was easy to find a list of APIs, it was more difficult to find basic instructions on how to use the workspace -- or even figure out that there was a workspace, let alone how to use the various objects and methods.

Once you save your workspace, it's on the public Web, although it's unlikely that anyone else will be able to find it unless you share the URL. And I found some of the samples not all that helpful in understanding the underlying data, even if they were visually striking.

Skill level: Intermediate.

Runs on: Any Web browser.

Learn more: To get started, I'd suggest the videos "Interface Basics" (7 minutes) and "Workspaces and Code." You can find a sample called The Pay Gap Between Men and Women Mapped at the website of British newspaper The Guardian.