How can I get RGB color of a surface?

How can I retrieve the displayed RGB color value of a surface? The following code draws a "line" colored to indicating a chosen value. In fact the line is really a surface, but it has a constant color as long as the caxis and colormap aren't changed. How do I retrieve this RGB color value, which is green in the example below? (My motivation is to use this RGB color for a text label).

figure;
x = 1:20; 
y = sin(x*pi/8);
vr = 200*ones(size(x)); % This value is used to assign the surface's color
% Unlike typical surfaces, the height doesn't vary
z = zeros(size(x));
% Make a very skinny surface that looks like a line
h = surface([x;x],[y;y],[z;z],[vr;vr],'facecolor','none',...
    'edgecolor','flat','linewidth',1) ; 
colormap(jet); % This affects the color of the surface
caxis([0 400]); % This also affects the color of the surface
colorbar;
% h is a surface (matlab.graphics.primitive.Surface)
get(h, 'color'); % Can't get the color of a surface so this fails here

The plot below shows that the surface appears as a green "line", and I'd like to retrieve the green color.

Answer 1

[Image Analyst]

I don't know what h is, since I didn't write that File Exchange code. Is h a 2-d matrix? If so, can't you just use the value of h as an index for your colormap, jet, to get the color for a particular height?

[KAE]

h is a surface (matlab.graphics.primitive.Surface). You should be able to run the code without downloading color_line from the File Exchange; I just wanted to credit it so I took it out of the question. You are right that I could define a color map and use it as a lookup table for the value assigned to vr above. I will try that. It just seems like if h appears as a certain color in the Matlab figure window, I should be able to access that color somehow.

[Image Analyst]

I don't know where your surface height is in this:

h = 
  Surface with properties:

         EdgeColor: 'flat'
         LineStyle: '-'
         FaceColor: 'none'
      FaceLighting: 'flat'
         FaceAlpha: 1
             XData: [2×20 double]
             YData: [2×20 double]
             ZData: [2×20 double]
             CData: [2×20 double]

I don't see anything like a 20x20 matrix with height values in it. I haven't used surface - is there a companion function that will produce such a surface? Some functions have companion functions.

[KAE]

I am a little confused about why you are asking about height when I am looking to retrieve the color. What am I missing?

[Image Analyst]

Well I can't see any surface, so I assume you have some surface where the color of the surface depends on the height of the surface, like this gives you:

[X,Y] = meshgrid(1:0.5:10,1:20);
Z = sin(X) + cos(Y);
C = X.*Y;
surf(X,Y,Z,C)
colorbar

[KAE]

I have a very funny surface: it is so skinny it appears like a green line in the example plot, and the values are all the same height (200 in the example). Why do this? Because the "line" color can indicate some relevant information about the plotted data. For example, you could plot price time series for various stocks and the color of each "line" indicates the number of people following it on social media. I think the lookup table recommendation is straightforward so I will pursue that!