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

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ker fang fang
ker fang fang 2014-11-2
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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回答（2 个）

Zoltán Csáti
Zoltán Csáti 2014-11-2
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
ker fang fang 2014-11-2
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;

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Image Analyst
Image Analyst 2014-11-2
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().

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