BOSTON — This afternoon at the Online News Association conference, Associated Press interactives producer Michelle Minkoff and WNYC’s data news director John Keefe held a hands-on, learn-by-doing session about creating quick data visualizations on a newsroom deadline.

Using free, open source tools and data sets, the barrier to entry for creating usable visualizations is lower than ever.

Michelle showed the audience how to make an interactive chart that graphs crime data using Google Chart Tools. She posted a full tutorial on her website and the downloadable source code for the visualization. Here are the key links you need to build a chart yourself:

• Michelle’s full tutorial
• A sample data set to use
• The source files (.zip)
• The extensive list of links from Michelle and other resources

John Keefe showed us how he quickly mapped hurricane evacuation zones during the days leading up to Hurricane Irene. The visualization had 57 times more traffic than he had originally projected. The whole thing was created using Google Fusion Tables. Here are some key links if you want to build your own map:

• The PDF version of John’s presentation
• Google Fusion Tools documentation
• Tool to import shape files to Google Fusion tables
• Fusion Tables layers builder
• Google Fusion tables
• His full list of relevant links

The overlayed legend in the top right corner of the map is simply a div that loads after the map, set with an absolutely position in the top right corner. Jeff copied the code from The Chicago Tribune — and a word of wisdom from Michelle: when it comes to this stuff, it’s ok to build off the code of others; in fact, that’s the point.

Follow @jkeefe and @michelleminkoff on Twitter for more or if you have questions.