MATLAB: Creating a heat map that would color different sectors of a circle

colormapplot

Hi all,

I have plotted 197 circles each with 3 sectors on a single plot. I have a value (a number between 1 and 30) associated with each sector and would like to create a heat type map that would color each sector of a circle based on its associated value. The values are stored in 3×197 matrix.

Any help is much appreciated.

Best Answer

Are these circles on an image? You forgot to show your plot/image so we have to just guess. Anyway, assuming the circle values are in an image with values rounded to the nearest integer (1 to 30), you can just apply a colormap to the figure

colorMap = jet(30);  % Create a colormap with 30 different colors.
% colorMap is just a numerical array at this point, 
% it's not been sent to the display adapter yet.  We'll do that next.
colormap(colorMap);  % Apply the colorMap to our figure.

Related Solutions

MATLAB: Creating a circle with segments of colour

Not sure what you mean by "adjustable in colour". The code below does the full colour wheel - it should give you a starting point anyway.

% Set parameters (these could be arguments to a function)
rInner = 80;     % inner radius of the colour ring
rOuter = 200;    % outer radius of the colour ring
ncols = 12;      % number of colour segments
% Get polar coordinates of each point in the domain
[x, y] = meshgrid(-rOuter:rOuter);
[theta, rho] = cart2pol(x, y);
% Set up colour wheel in hsv space
hue = (theta + pi) / (2 * pi);     % hue into range (0, 1]
hue = ceil(hue * ncols) / ncols;   % quantise hue 
saturation = ones(size(hue));      % full saturation
brightness = double(rho >= rInner & rho <= rOuter);  % black outside ring
% Convert to rgb space for display
rgb = hsv2rgb(cat(3, hue, saturation, brightness));
% Check result
imshow(rgb);

MATLAB: Pseudo-color a moving object track based on its length from origin.

Use an overlay. For more info, see:

http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/

http://www.mathworks.com/matlabcentral/answers/104889-how-to-overlay-a-foreground-image-over-a-background-image

Best Answer

Related Solutions

MATLAB: Creating a circle with segments of colour

MATLAB: Pseudo-color a moving object track based on its length from origin.

Related Question