# Visualizing 28 different variables with 28 different colors?

ColorBrewer seems to be very useful in selecting a color pallet to represent factors that have up to 12 possible values.

I have 28.

Is it a horrible idea to represent 28 variables with color? If so, could you suggest an alternative visual indicator?

Currently I'm using the colors for column side colors in a heatmap shown below. As you can see, the Strain column is not very informative:

• Is it absolutely necessary to use all 28 of them? You could use some dimensionality reduction technique and view them, if not necessary. Oct 29 '17 at 21:08
• Interesting. Dimenaionality reduction on categorical variables? Can you say more? Oct 29 '17 at 21:09
• An unsupervised method may be Self-Organizing maps. Somoclu is a great tool. It may also help with the visualization. Oct 29 '17 at 21:25
– Emre
Oct 30 '17 at 4:10
• Ideally, don't really on colour as your only method for distinguishing important information. Colour blindness is a thing. Sep 28 '18 at 11:45

So I merged d3 catagory 20 with the first few from d3 category20b which was inspired from this heatmap tools heatmap tool's source code: