In my previous post on plotting topographies in R, ERP Visualization: Creating topographical scalp maps: part 1, I was aiming for maximum comparability with EEGLAB defaults. That meant I used the ‘jet’ colour map, which is what I’m most used to using. You may have noticed that there was no default jet colour map - I had to define one manually. While jet produces nice, punchy looking images, there are a heap of problems associated with it.
As well as ERPs or time-frequency plots from individual channels, it’s always useful to see topographical maps of our data. It’s a nice way to see what’s going on across the whole head, showing us whether effects are broadly or narrowly distributed across the whole scalp. So now I’m going to show you how to do topographical plots in R. I want to first of all thank alexforrance and Harold Cavendish over on Stack Overflow for being the source of much of the code I’ve adapted here.