CODEWITHSUNDEEP
matlabplot
Jiu
Jiu

Reputation: 11

How can I plot a pattern of random points in a specific region?

I wrote this matlab code to plot a set of random points in a specific region of the graph. I need to set the xlim and ylim in the range (1,512) (-1,512) but when I substituted this values in the following code nothing is plotted.I tried also to insert the range 150,350 that represent the central part of the graph in which I want to plot all points. How can I fix the problem?

x = rand(1, 50);
y = rand(1, 50);
plot(x,y,'.')
xlim([-0.2 1.2])
ylim([-0.2 1.2])

Upvotes: 0

Views: 771

Answers (1)

Suever
Suever

Reputation: 65440

The output of rand is going to contain values between 0 and 1 so when you expand the x and y limits to [1 512] all data is going to be shown within the lower 1/512th of the axes and therefore you can't see the individual points.

If you want your random values to actually span the range [1 512] (for x) and [-1 512] (for y), then you'll want to alter the output of rand accordingly.

x = 1 + rand(1, 50) * 511;
y = rand(1, 50) * 513 - 1;

plot(x, y, '.')

xlim([1 512]);
ylim([-1 512]);

enter image description here

A more general solution would be to create an anonymous function which creates random numbers within the specified range

myrand = @(r, varargin)rand(varargin{:}) * diff(r) + min(r);

xrange = [1 512];
yrange = [-1 512];
x = myrand(xrange, 1, 50);
y = myrand(yrange, 1, 50);

plot(x, y, '.')

xlim(xrange);
ylim(yrange);

Or if you want your points to be within a certain region inside of the axes

x = myrand([50 100], 1, 50);
y = myrand([50 100], 1, 50);

plot(x, y, '.');

xlim([0 150])
ylim([0 150])

Upvotes: 2

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