Problem with adjusting custom colormap and colorbar

Hello everyone

How to adjust a color bar in this way?

lower than 0.05 = white

0.05 ~ 0.1 = red

0.1 ~ 0.2 = yellow

0.2 ~ 0.3 = green

0.4 ~0.5 = blue

greater than 0.5 = black

Here is my try:

mycolormap = [1 1 1; 1 0 0; 1 1 0; 0 1 0; 0 0 1;0 0 0 ];
colormap (mycolormap)
caxis([0.05, 0.5])
c=colorbar('XTickLabel',{'0.05','0.1','0.2','0.3','0.4','0.5'});

But unfortunately here is my color bar:

which the colors not correctly showing and also color bar tick labels are not consonant.

Thanks

Answer 1

[Walter Roberson]

The colormap process is uniform mapping. All bars are the same size. However you can assign the same color to multiple bars.

 white
 red
 yellow 
 yellow 
 green 
 green 
 blue 
 blue
 black

also note that for mapping purposes, you cannot say "less than" and assign a color to that condition. You need to assign a slot of equal size to the other slots. This can require you to expand your caxis

[BN]

Thank you

[Walter Roberson]

See also https://www.mathworks.com/matlabcentral/fileexchange/69470-custom-colormap