# What do you call a graph where you color a grid based on some measure?

I mean something like this chart showing the frequencies of a user's public contributions on GitHub.

I really like this kind of chart, as I think that they display the intended data in a really nice and easy to see way, but I have no clue what they are called, so I can't look for a library to help me generate them. Can someone tell me the name of this type of graph / chart?

I think you are looking at a heat map. The one you link to is a fancy interactive version that presumably requires java code. In R the function would be ?heatmap. There is a tutorial for how to make them in R here. This is the initial output of their code: