convert Axis to matrix of coordinates

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jack 2015-8-6

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回答： Walter Roberson 2015-8-7

I need you help in converting axis to matrix of coordinates so that i will get the coordinates ,according the axis, of all points in the figure. Is this feasible , can It be done?

For example : look in http://imgur.com/YmUPl0S

here the x coordinate should start about ~-4.3 and end in ~7.3 and the y coordinate should start about ~-4.3 and end in ~4.2 therefore i need all these coordinate in this figure so that for each point i will know it's coordinates according the axises. So can i make a matrix containing all these coordinates?

Please advise.

Thanks in advance.

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Azzi Abdelmalek 2015-8-6

编辑：Azzi Abdelmalek 2015-8-6

[converting axis to matrix of indexes], what does that mean? indices of what?

jack 2015-8-6

I have rewritten my question to make it more understandable.

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Answer 1

Azzi Abdelmalek 2015-8-6

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https://ww2.mathworks.cn/matlabcentral/answers/232601-convert-axis-to-matrix-of-coordinates#answer_188436

编辑：Walter Roberson 2015-8-7

在 MATLAB Online 中打开

Jack, you are not converting anything. You are, maybe, looking for how to get the x-data and y-data from the plot. For example

x=0:0.21:10;
y=sin(x);
plot(x,y)

To get the data

h=findobj(gca,'type','line')
x=get(h,'xdata')
y=get(h,'ydata')

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Azzi Abdelmalek 2015-8-7

What "all" means? in theory there are infinity of points. How many points do you want?

jack 2015-8-7

编辑：jack 2015-8-7

if i take the figure and convert it to image i can access each pixel in the image , here i want that same but with coordinates regarding the axis of the figure. So can i take the figure and create a matrix of coordinates regarding the axis ?

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Answer 2

Walter Roberson 2015-8-7

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If what you have is a figure object (not an image) then findobj() the axes objects and for each of them get() the XLim and YLim properties. "All possible coordinates" of what is displayed will then be the union of the those regions. There may also be graphic objects that are outside what is visible; it is not clear that you are interested in those.

If what you have is an image, then see Jiro's File Exchange contribution