how to get/extract x,y values from scatter function

Hi,

I am currently plotting the X,Y coordinates using scatter function as below.

scatter(x(:,1),x(:,2),[],x(:,3),'filled')

I would like to get the x,y value which is being plotted with different colors, could you please do help me out here.

thank you.

Answer 1

[Bhaskar R]

You need to apply thresholding to the 3rd column of the x variable upto blue colour as it is normalized colour. If you apply colourbar to the plot you can get idea how to choose threshold value

Demo:

>> x = rand(10, 2); % X, Y data
>> x(:, 3) = 1:10;  % colour data where 1 indicates complete blue, 2 - somewhat diluted colour so it is normalized
>> ax  = scatter(x(:,1),x(:,2),[],x(:,3),'filled');colorbar;

If you see the colorbar is the axes upto 5 level values are blue as you require, so get the values using CData properties of ax

>> x_values = ax.XData(ax.CData <5);
>> y_values = ax.YData(ax.CData <5);

Hope you get my point

[SatyaPrakash Gupta]

the third element is already considerd as colorbar in the scatter.

C determines the colors of the markers. When C is a vector the same length as X and Y, the values in C are in early mapped to the colors in the current colormap.

so i think we dont have to write colorbar at the end which you have suggested

[Bhaskar R]

For the understanding purpose i included colorbar

[SatyaPrakash Gupta]

I think adding colorbar to the code will help to determine the range of the color , therefore it is a good idea to add colorbar

if there is a for loop for 6000 times and the 3rd element keeps changing , as soon as the loop is finished , then we can get the total limit /range of the colorbar , please do correct me if my udnerstanding is wrong ?

Also i would like to define the threshold between -10 to 10 , how can i do it because the code provided by you takes only one comparision ?

Answer 2

[darova]

Use handle

h = scatter(..)
get(h,'xdata')

[SatyaPrakash Gupta]

with the above suggestion , i think the value will be the same as compared the input provided to the scatter.

I want to extract/get the value of X,Y which has being plotted with different colors like for example.

when the scatter color is blue, i want to get all the X Y coordinates of blue color similarly for Geen, Yellow