using heatmap of a nxm matrix for outlier detection

I have a nxm matrix of positive real values. I would like to make a heatmap with values from 1 to maximum with color white to deep red and from 1 down to zero with color white to say deep blue.

Answer 1

[Image Analyst]

I think you mean "colormap" rather than "heatmap". Try this:

>> colormapeditor

[Alvin Stroyny]

heatmap applies a single color gradient from white to dark (i.e. cold to hot). Instead of applying the white to the lowest values, I would like to define "room temperature" (i.e. the mean(mean(x)) ) and have say a red color gradient from white to red = room temp to hottest, and a reverse say blue gradient from white to dark blue = room temperature to coldest. I think the question is can the heatmap use a dual color gradient?

[Image Analyst]

Looks like this is the relevant page with instructions:

https://www.mathworks.com/help/matlab/creating_plots/change-mapping-of-data-values-into-the-colormap.html?s_tid=srchtitle_Control%20Colormap%20Limits_1

Follow that procedure to set up your colors with the pattern/gradients you want.