When creating infographics I find ColorBrewer's map color palettes very helpful (especially in creating maps that are readable by the colorblind). It provides me with colors to represent different "levels" of sequential data.
Currently I am determining the "levels" by hand (10+, 20+, 30+) but this is definitely not the best way to do it.
If I have an array of numbers, is there a plug-in, application, or website, which will take in these numbers, and spit out the different "levels" that I need?