Plotting a 2D Contour from data (A variable with its XY coordinates)

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Peter 2014-12-29

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评论： Sean de Wolski 2014-12-29

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Hello!

I need to plot a 2D Contour form data. I have a variable called "Intensity" with 224x1 values and I have a variable called "XYAxis" with the corresponding coordinates of this Intensity (224 points (X,Y)).

What i want to do is to plot both variables, to have a contour2D with the distribution of the Intensity among the points analized (each value of Intensity corresponds to one point(X,Y).

I have tried:

Contour (XYAxis,Intensity);

But it only displays an empty plot and the axis are not those i desire (i want the contour to be like scattered).

Any idea? Maybe TriScatteredInterp()?? but i need the contour to be 2D

Thanks in advanced

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Sean de Wolski 2014-12-29

Could you provide a small set of sample data?

Peter 2014-12-29

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Sure,

For example, I have one variable called " XYAxis " (224x2 double) this way (1º column is X and 2º Column is Y):

0
5
10
20
30
... until 224 points

And I have another variable called " Intensity " like this:

5
8
9
10
11
...
until 224 values

So each value of "Intensity" corresponds with one value of "XYAxis" And i want to plot it with a contour 2d. Thanks

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采纳的回答

Sean de Wolski 2014-12-29

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https://ww2.mathworks.cn/matlabcentral/answers/168413-plotting-a-2d-contour-from-data-a-variable-with-its-xy-coordinates#answer_163553

编辑：Sean de Wolski 2014-12-29

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% Synthetic Data  
xy = rand(20,2);
intensity = rand(20,1);
% Interpolate to grid
interpolant = scatteredInterpolant(xy(:,1),xy(:,2),intensity);
% Grid
[xx,yy] = meshgrid(linspace(0,1,10));  % replace, 0 1, 10 with range of your values
% Interpolate
intensity_interp = interpolant(xx,yy);
contourf(xx,yy,intensity_interp)

You'll have to interpolate it to a grid and then call contour.

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Peter 2014-12-29

编辑：Peter 2014-12-29

I mean "automatically", with the names of the axis on it and a legend

Sean de Wolski 2014-12-29

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xlabel('whatever x is')
ylabel('whatever y is')
filename = ['file' num2str(1) '.png'] % replace 1 with whatever you want automatically created.
saveas(gcf,filename)