MATLAB: How to make a circle MarkerSize on a plot equal to a specific diameter relative to the scale being used

circlemarkersizeplot

I have a question about using MarkerSize for 'Marker' = 'o' using the plot function

MarkerSize is given in points. I would like to set the diameter of the Marker 'o'

Is there a conversion to obtain a numerical value given by the scale you're using.

For example, on a degrees plot: plot(A, B, 'Marker', 'o', 'MarkerSize', .75)

where A and B are in degrees.

I would like the diameter to equal .75 degrees. Thanks for your help !

Best Answer

It could be done in theory, through a multistep process involving finding the plotting area of the axes in units in points, and relating that to the xlim or ylim to determine the proper ratio.

Finding the actual plotting area inside the box limits is tricky in my experience; I'm not sure I have ever managed to do it.

This is a case where scatter() does not help; I generally turn to scatter() when point plotting via plot() is not sufficiently flexible, but scatter() uses points for its marker size as well.

Hmmm... you could probably rectangle() circles in places at the appropriate locations (the rectangle() routine can draw circles.)

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MATLAB: Help moving an object

Hello,

I have cleaned up a little bit of your code. You can create a function that will plot a cornerlight on the position to make it even more compact. The issue was with rectangle function and hold on, rectangle plots each time a new one when you call it. Getting a handle for rectangle and changing its Position property as shown below can solve your issue.

axis equal
hold on;
format long g; format compact;
%%-lower right corner light------------------------
LRCL = rectangle('Position', [0+64 0+30 2 4],'Curvature', 0.2,'FaceColor', 'k');
darkGray = [0.2, 0.2, 0.2];
green = [0, 132, 80] / 255;
yellow = [239, 183, 0] / 255;
red = [184, 29, 19] / 255;
pos = [0.5+64 2.75+30 1 1];
rectangle('Position', pos, 'Curvature',[1 1], 'FaceColor', darkGray)
pos = [0.5+64 1.5+30 1 1];
rectangle('Position', pos, 'Curvature',[1 1], 'FaceColor', darkGray)
pos = [0.5+64 0.25+30 1 1];
rectangle('Position', pos, 'Curvature',[1 1], 'FaceColor', red)
%%-upper left corner ---------------------------------
ULCL = rectangle('Position', [0+35 0+64 2 4],'Curvature', 0.2,'FaceColor', 'k')
darkGray = [0.2, 0.2, 0.2];
green = [0, 132, 80] / 255;
yellow = [239, 183, 0] / 255;
red = [184, 29, 19] / 255;
pos = [0.5+35 2.75+64 1 1];
rectangle('Position', pos, 'Curvature',[1 1], 'FaceColor', red)
pos = [0.5+35 1.5+64 1 1];
rectangle('Position', pos, 'Curvature',[1 1], 'FaceColor', darkGray)
pos = [0.5+35 0.25+64 1 1];
rectangle('Position', pos, 'Curvature',[1 1], 'FaceColor', darkGray)
%%-lower left corner light-------------------------------
rectangle('Position', [0+30 0+35 4 2],'Curvature', 0.2,'FaceColor', 'k')
darkGray = [0.2, 0.2, 0.2];
green = [0, 132, 80] / 255;
yellow = [239, 183, 0] / 255;
red = [184, 29, 19] / 255;
pos = [2.75+30 0.5+35 1 1];
rectangle('Position', pos, 'Curvature',[1 1], 'FaceColor', green)
pos = [1.5+30 0.5+35 1 1];
rectangle('Position', pos, 'Curvature',[1 1], 'FaceColor', darkGray)
pos = [0.25+30 0.5+35 1 1];
rectangle('Position', pos, 'Curvature',[1 1], 'FaceColor', darkGray)
%%-upper right corner light--------------------------
rectangle('Position', [0+65 0+65 4 2],'Curvature', 0.2,'FaceColor', 'k')
darkGray = [0.2, 0.2, 0.2];
green = [0, 132, 80] / 255;
yellow = [239, 183, 0] / 255;
red = [184, 29, 19] / 255;
pos = [2.75+65 0.5+65 1 1];
rectangle('Position', pos, 'Curvature',[1 1], 'FaceColor', darkGray)
pos = [1.5+65 0.5+65 1 1];
rectangle('Position', pos, 'Curvature',[1 1], 'FaceColor', darkGray)
pos = [0.25+65 0.5+65 1 1];
rectangle('Position', pos, 'Curvature',[1 1], 'FaceColor', green)
k=0;
% defining red car
redCar = rectangle('FaceColor','red','Edgecolor','red','Position',[55 k 3 7]);
while k<=90
    redCar.Position = [55 k 3 7];
    k=k+1;
    pause(0.1)
end
% defining magenta car 
k=65;
magentaCar = rectangle('FaceColor','magenta','EdgeColor','magenta','Position',[43 k 4 8])
while k<=65 && k>=0
    k=k-1;
    magentaCar.Position = [43 k 4 8];
    pause(0.1)
end
pause(5)

MATLAB: Draw ellipse in image

See the FAQ: http://matlab.wikia.com/wiki/FAQ#How_do_I_create_an_ellipse.3F

Also see my attached demos.

Best Answer

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MATLAB: Help moving an object

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