How do I get the x,y coordinates from the scatter graph I generated?

Question

ker fang fang 2014-11-2

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https://ww2.mathworks.cn/matlabcentral/answers/160976-how-do-i-get-the-x-y-coordinates-from-the-scatter-graph-i-generated

回答： Image Analyst 2014-11-2

Hi, I need to get those values to put into an equation. Can anyone help me? Here is the example code that I wrote. Thanks.

xrange = 0:100;
yrange = 0:100;
a= randi(numel(xrange),15,1); %randomly choose xcoordinate
b = randi(numel(yrange),15,1); %randomly choose ycoordinate
scatter(a(:),b(:),2000,'r')
for k=1:numel(a,b)
      text(a(k),b(k),['(' num2str(a(k)) ',' num2str(b(k)) ')'])
end

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Answer 1

Zoltán Csáti 2014-11-2

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https://ww2.mathworks.cn/matlabcentral/answers/160976-how-do-i-get-the-x-y-coordinates-from-the-scatter-graph-i-generated#answer_157432

在 MATLAB Online 中打开

You created the scatter plot in view of vectors a and b. So those are the coordinates. Supposing you only have the scatter plot and you want to extract the coordinates:

   sc = findobj(gca,'Type','hggroup');
   xCoord = get(sc, 'XData');
   yCoord = get(sc, 'YData');

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ker fang fang 2014-11-2

在 MATLAB Online 中打开

but there is no response or any answer by that equation, it seem like the program after the for loop, does not read it. how to solve it?

the code

if true
  % code
xrange = 0:100;
yrange = 0:100;
a= randi(numel(xrange),15,1); %randomly choose xcoordinate
b = randi(numel(yrange),15,1); %randomly choose ycoordinate
scatter(a(:),b(:),2000,'r')
for k=1:numel(a,b)
    text(a(k),b(k),['(' num2str(a(k)) ',' num2str(b(k)) ')'])
end
sc = findobj(gca,'Type','hggroup');
a = get(sc, 'XData');
b = get(sc, 'YData');
f = a + b.^2;

Zoltán Csáti 2014-11-2

I do not really know what you want. You have vectors a and b at disposal.

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Answer 2

Image Analyst 2014-11-2

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https://ww2.mathworks.cn/matlabcentral/answers/160976-how-do-i-get-the-x-y-coordinates-from-the-scatter-graph-i-generated#answer_157462

The answer to your question is that you already have "a" and "b" so you have the "x,y coordinates" that you're requesting. Like Zoltan already told you, there is no need to call get() to extract it from the plot when it was YOU who created the plot - you must have the coordinates to create the plot in the first place.

If you want some kind of interpolated surface for every value of a and b, even those where you don't have any training data, try scatteredInterpolant().