how add intensity/frequency to the scatter plot

Hi, I would like to scatter plot these two vectors: X=[0 0 1 2 0 1 1 0]; Y=[1 1 1 1 2 0 0 2]; and had the frequency of occurrence in the color or in the size of the points, something like the attached pic

Answer 1

[Pawel Jastrzebski]

Consider the code below but also check the documentation for:

• Scatter plot

   X=[0 0 1 2 0 1 1 0]; 
   Y=[1 1 1 1 2 0 0 2];

   % find the freqency vector

   minVal = min(Y)
   maxVal = max(Y)

   vectorOfvalues = minVal:maxVal

   howMany    = Y'==vectorOfvalues
   howManySum = sum(howMany);

   % this line nicely show how the occurance of a value
   % 1st row: value
   % 2nd row: occurance
   howManySum = [vectorOfvalues; howManySum]

   % pre-allocation
   occurence = zeros(1,length(Y));

   for i=1:length(howManySum)
       occurence(Y==howManySum(1,i)) = howManySum(2,i);
   end

   Y
   occurence

   % I've added the factor of 50 for the occurance
   % so the diffrence between the dot sizes is visible
   figure
   scatter(X,Y,50*occurence)

[didi]

Hi! thansk for your answer, but I got an error here: howMany = Y'==vectorOfvalues matrix dimensions must agree

[Pawel Jastrzebski]

• IF you literally copied/pasted my code - it should work (see attached live script and the .pdf)
• This error appears when you're trying to compare to row vectors or two column vectors - make sure one of the vector is in column orientation and the other one in the row orientation - see example below
• Try clearing the workspace of the variables that you use within this code - make sure that whatever is created with the code, is created for the first time

>> Y

Y =

       1     1     1     1     2     0     0     2

>> vectorOfvalues

vectorOfvalues =

       0     1     2

>> howMany = Y ==vectorOfvalues
Matrix dimensions must agree.

>> Y = Y'

Y =

       1
       1
       1
       1
       2
       0
       0
       2

>> howMany = Y ==vectorOfvalues

howMany =

    8×3 logical array

     0   1   0
     0   1   0
     0   1   0
     0   1   0
     0   0   1
     1   0   0
     1   0   0
     0   0   1

[didi]

Thanks for the your help. I still have the == problem but i solved in this way:

howMany1 = Y'==vectorOfvalues(1) howMany2 = Y'==vectorOfvalues(2) howMany3 = Y'==vectorOfvalues(3) howMany = [howMany1 howMany2 howMany3]

[Pawel Jastrzebski]

Which version of Matlab do you use?

[didi]

R2015a..indeed maybe it can be related to the version

[Pawel Jastrzebski]

Must be. The code:

howMany    = Y'==vectorOfvalues

uses so called implicit expansion which was introduced in version R2016B.