title: What's a good strategy to get a decent overview of big correlation matrices or pairs?
body: <p>Often some <code>data.frame</code> contains 20+ variables and you want to get a first overview (of the correlation structure). Even on a 30" screen you run quickly out of space and it remains hard to grasp the message. Are there any established strategies to highlight what's important? I am aware this question is somewhat general, but I wondered over and over again and never had the panacea to cure it. And yup, I heard of <code>summary</code>.</p>