choose line color based on intensity

Hi,

I have a plot with several concentric circles, and a vector C which gives a value for each radius used. I would like each circle in the plot to have a color based on the intensity specified by C. Is there a way to do this?

Thanks!

Answer 1

[Image Analyst]

Maria: You can use the 'EdgeColor' property of rectangle() to draw circles in different colors. You can use the built-in colormap palettes, like jet() or hsv() or hot() or whatever, to create a list of colors. See this code:

numRadii = 20;
colors = jet(numRadii);
xCenter = 50;
yCenter = 60;
for r = 1 : numRadii
  leftTopWidthHeight = [xCenter-r/2, yCenter-r/2, r, r];
  rectangle('Position', leftTopWidthHeight,...
    'Curvature', [1 1], ...
    'LineWidth', 4, ...
    'EdgeColor', colors(r, :))
  hold on;
  axis equal
end
grid on;
% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
% Get rid of tool bar and pulldown menus that are along top of figure.
set(gcf, 'Toolbar', 'none', 'Menu', 'none');
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off')

Answer 2

[Haneya Qureshi]

I am having the same problem, but I would like to color each circle according to the intensity associated with it. In other words, I have 10 circles, each with a certain radius and each radius represents a certain intensity. I would like to color circles according to that intensity and then display a colour map of intensity

[Image Analyst]

Translate the radius to a row in your colormap and use that color. For example if you have radii that go from 1 - 500, and your radius is 73, and your colormap has 256 rows, then the row containing the color you want to use is

colormapRow = round( (73/500) * 256 );
colorToUse = yourColorMap(colormapRow, :);