22 Free Tools for Data Visualization and Analysis
What it does: OpenStreetMap is somewhat like the Wikipedia of the mapping world, with various features such as roads and buildings contributed by users worldwide.
What's cool: The main attraction of OpenStreetMap is its community nature, which has led to a number of interesting uses. For example, it is compatible with the Ushahidi mobile platform used to crowdsource information after the earthquakes in Haiti and Japan. (While Ushahidi can use several different providers for the base map layer, including Google and Yahoo, some project creators feel most comfortable sticking with an open-source option.)
Drawbacks: As with any project accepting public input, there can be issues with contributors' accuracy at times (such as the helicopter landing pad someone once placed in my neighborhood -- it's actually quite a few miles away). Although, to be fair, I've encountered more than one business listing on Google Maps that was woefully out of date. In addition, the general look and feel of the maps isn't quite as polished as commercial alternatives.
Skill level: Advanced beginner to intermediate.
Runs on: Any Web browser.
Learn more: See the Quick Tutorial on the OpenLayers site.
Temporal data analysis
If time is an important component of your data, traditional timeline visualizations may show patterns, but they don't allow for sophisticated analysis or a great deal of interaction. That's where this project comes in.
What it does: This desktop software is for analyzing data points that involve a time component. In a demo I wrote about last summer, creators Fernanda Viégas and Martin Wattenberg -- the pair behind the Many Eyes project who are now working at Google -- showed how TimeFlow can generate visual timelines from text files, with entries color- and size-coded for easy pattern spotting. It also allows the information to be sorted and filtered, and it gives some statistical summaries of the data.
What's cool: TimeFlow makes it incredibly easy to interact with data in various ways, such as switching views or filtering by criteria such as date ranges or earthquakes of magnitude 8 or more. The timeline view offers a slider so you can zero in on a time period. While many applications can plot bar graphs, fewer also offer calendar views. And unlike Web-based Google Fusion Tables, TimeFlow is a desktop application that makes it quick and painless to edit individual entries.
Drawbacks: This is an alpha release designed to help individual reporters doing investigative work. There are no facilities for publishing or sharing results other than taking a screen snapshot, and additional development appears unlikely in the near future.
Skill level: Beginner.
Runs on: Desktop systems running Java 1.6, including Windows and Mac OS X.
Learn more: Check out Top tips.
Note: If you're looking to publish visualized timelines, better options include Google Fusion Tables, VIDI or the SIMILE Timeline widget.
Some data visualization geeks think word clouds are either not very serious or not very original. You can think of them as the tiramisu of visualizations -- once trendy, now overused. But I still enjoy these graphics that display each word from a text file once, with the size of the words varying depending on how often each one appears in the source.
What it does: Several tools mentioned previously can create word clouds, including Many Eyes and the Google Visualization API, as well as the website Wordle (which is a handy tool for making word clouds from websites instead of text files). But if you're looking for easy desktop software dedicated to the task, IBM's free Word-Cloud desktop application fits the bill.
What's cool: This is a quick, fun and easy way to find frequency of words in text.
Drawbacks: Because it's trying to ignore words such as "a" and "the," the basic configuration can miss some important terms. In my tests, it didn't know the difference between "it" and "IT," and completely missed "AT&T."
Skill level: Advanced beginner. This app runs on the command line, so users should have ability to find file paths and plug them into a sample command.
Runs on: Windows, Mac OS X and Linux running Java.
Learn more: Check the examples that come with the download.
Social and other network analysis
These tools use a pre-Facebook/Twitter definition of "social network analysis" (SNA), referring to the discipline of finding connections between people based on various data sets. Investigative journalists have used such tools to, for example, find links between people who are involved in development projects or who are members of various boards of directors.
An understanding of statistical theories of network node analysis is necessary in order to use this category of software. Since I've only had a very basic introduction to that discipline, this is one category of tools I did not test hands-on. But if you're seeking software to do such analysis, one of these might meet your needs.
What it does: Billed as a Photoshop for data, this open-source beta project is designed for visualizing statistical information, including relationships within networks of up to 50,000 nodes and half a million edges (connections or relationships) as well as network analyses of factors such as "betweenness," closeness and clustering coefficient.
Runs on: Windows, Linux, Mac OS X running Java 1.6.
Learn more: Try this Quick Start tutorial (PDF).
What it does: This Excel plug-in displays network graphs from a given list of connections, helping you analyze and see patterns and relationships in the data.
NodeXL merges the older and current definitions of SNA. It's "optimized for analyzing online social media -- it includes built-in connections to query the APIs of Twitter, Flickr and YouTube, allowing you to draw networks of users and their activity," according to Peter Aldhous, San Francisco bureau chief for New Scientist magazine.
It also handles e-mail and conventional network analysis files (including data created by the popular -- but not free -- analysis tool UCINET).
Runs on: Excel 2007 and 2010 on Windows.
Learn more: Download this detailed free NodeXL tutorial (PDF) or these basic step-by-step instructions on analyzing your own Facebook social network (PDF). One Facebook app for downloading your own friend information for use in NodeXL is Name Gen Web.