set colormap values to an array

Hello,

I have a 22x1 array that I'd like to assign to a colorscale (jet) so that each value has a corresponding corresponding color

>> colorpost

colorpost =

   -1.4721
  -11.3430
   23.4227
    7.0674
   -2.7839
   42.3308
   -2.6353
    0.1617
    6.3158
  -20.6096
    2.6023
    3.1703
    5.8185
   -4.1358
    6.9481
   -5.1080
   24.6877
   -5.1542
  -17.9669
    1.8017
  -23.3427
  -15.8499
 

But when I do the following it doesn't work

>> c=jet(colorpost)
Error using  / 
Matrix dimensions must agree.

Error in jet (line 23)
u = [(1:1:n)/n ones(1,n-1) (n:-1:1)/n]';

I've seen a similar problem here but it doesn't seem to help me since that array is all integers https://www.mathworks.com/matlabcentral/answers/897552-get-colormap-values-corresponding-to-array-values

Answer 1

[Walter Roberson]

colorpost = [
   -1.4721
  -11.3430
   23.4227
    7.0674
   -2.7839
   42.3308
   -2.6353
    0.1617
    6.3158
  -20.6096
    2.6023
    3.1703
    5.8185
   -4.1358
    6.9481
   -5.1080
   24.6877
   -5.1542
  -17.9669
    1.8017
  -23.3427
  -15.8499
  ];

cmap = jet();
numcol = size(cmap,1);

cps = floor(rescale(colorpost, 1, numcol));
colorized_cp = permute(cmap(cps,:), [1 3 2]);

image(colorized_cp)

[bsriv]

Thank you!

Answer 2

[Image Analyst]

Try this:

colorpost =[...
    -1.4721
    -11.3430
    23.4227
    7.0674
    -2.7839
    42.3308
    -2.6353
    0.1617
    6.3158
    -20.6096
    2.6023
    3.1703
    5.8185
    -4.1358
    6.9481
    -5.1080
    24.6877
    -5.1542
    -17.9669
    1.8017
    -23.3427
    -15.8499];
% Specify the number of colors to be the same as the number of elements in colorpost.
numColors = numel(colorpost)
% Create a colormap.
cmap = jet(numColors);
% Assume min value is cmap(1, :) and max value is cmap(end, )
% Get color sorted in the same way as colorpost (or you could make a dictionary)
[sortedColorpost, sortOrder] = sort(colorpost, 'ascend');
assignedColors = cmap(sortOrder, :);

Is it what you want?

[bsriv]

perfect thank you!

[Walter Roberson]

This assigns one color per element, even if two elements are close or even identical. The color is not proportional to the value.

The solution I gave scales entries according to relative value through the span of values, and so is suitable for color representing relative value.