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How to associate and color points based on distance or search radius and contour them?

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Abdelrahman Abdeltawab
Abdelrahman Abdeltawab on 26 Nov 2016
Commented: Xel Ch on 27 Jun 2018
I have scatter plot shown in first image
what is the best method to reach the result in second image?


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Answers (1)

Jose Lara
Jose Lara on 5 Dec 2016
Abdelrahman, if you know the temperature for each of the coordinate given, you could create your own gradient of color.  If you have a matrix with the coordinates, for example:
coords = [1 2 3 4 5 6 7 8; 2 5 7 8 9 9 0 3];
then you may iterate through each point and designate it's own color depending on the resulting temperature. If the equation for the temperature is as follows:
T = x^2 +y/2 +1;
using a for loop, you can iterate through each point and plot with the correct color. Example code is shown below:
for i = 1:8 %number of coordinates
    hold on
    xi = coords(1,i);
    yi = coords(2,i);
    T =  xi^2 + yi/2 +1;
    if T > 10;
    elseif (T<10) && (T>8)
    elseif (T<8) && (T<4)
where the third argument of the ''plot'' function will be the color of the point and the marker type. You may separate the temperatures with more colors by using a RGB color values such as [1 0 0] for red and [1 1 1] for white. 
Check out the following link for more information on the ''plot'' function:


Abdelrahman Abdeltawab
Abdelrahman Abdeltawab on 6 Dec 2016
Thanks alot Jose, but my what i wanted is for each point in the scatter find the nearby points and cluster them or highlight them
Xel Ch
Xel Ch on 27 Jun 2018
Hi Abdelrahman. I am looking to do something similar in Matlab, so was wondering if you were ever able to get this issue resolved? And if so, what did you do? Thank you!

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