I am trying to do a scatter plot with 2 different Y axes with different scales using imported data on a graph.

I am trying to make a scatter plot of two data sets with the same x axis but two different y axis. I see how to do it with a line plot but can not seem to figure it out with a scatter plot with imported data from a table. Any help would be appreciated. Thank you.

Answer 1

[KSSV]

x1 = rand(1,10) ;
y1 = rand(1,10) ;
z1 = sqrt(x1.^2+y1.^2) ;
yyaxis left
scatter(x1,y1,[],z1,'filled','O')
x2 = x1;
y2 = rand(1,10)+10 ;
z2 = sqrt(x2.^2+y2.^2) ;
yyaxis right
scatter(x2,y2,[],z2,'filled','s')

Answer 2

[Bora Eryilmaz]

% Dataset in a table
T = table((1:100)', cumsum(rand(100,1)), cumsum(rand(100,1)), 'VariableNames', {'Time', 'Data1', 'Data2'})

T = 100×3 table
    Time     Data1      Data2 
    ____    _______    _______

      1     0.48783    0.25794
      2     0.52543     1.0037
      3      1.1565     1.5112
      4      1.7177     1.8596
      5      2.4556     1.9385
      6      2.8473     2.7949
      7      3.1231     3.0652
      8      4.0823     3.3043
      9      4.7703     3.4385
     10      5.5753     4.2247
     11      6.3436     4.5791
     12      6.7197     5.3782
     13      7.0281     6.0013
     14      7.7479     6.9337
     15      8.3779     7.3871
     16      9.2435     7.4251

% Left plot
x = T.Time;
y = T.Data1;
yyaxis left
scatter(x,y)
ylabel('Data 1')

% Right plot
z = T.Data2;
yyaxis right
scatter(x,z)
ylabel('Data 2')

[Yulia Gitter]

What if we are not doing it based off a function but instead off a data set in a table imported from excel?

[Bora Eryilmaz]

See my updated answer.

[Yulia Gitter]

Ah thank you so much!

[Yulia Gitter]

Hi appolgoies, I could not quite get it the way you did. I imported the data from excel so its not a table within the script but instead reading from one. In the figure below I have it showing how I have the data imported. Since its not on the actual script, I am wondering if there is a way to do the two Y axes with it imported from excel.

[Benjamin Kraus]

Where the data originates is not relevant, if the data is stored in MATLAB table, you can use yyaxis the way @Bora Eryilmaz shows in his post.

The code from your screen shot is calling readtable, which reads a table (in this case from an Excel spreadsheet) and creates a MATLAB table. On the right side of your screenshot you can see you have a MATLAB table with 1568 rows and 7 variables. Your data is in a table, so you can use yyaxis.

For example:

yyaxis left
scatter(dec22LN2testingPROCESSEDS2.DelTmin,dec22LN2testingPROCESSEDS2.OutletK)
yyaxis right
scatter(dec22LN2testingPROCESSEDS2.DelTmin,dec22LN2testingPROCESSEDS2.MassFlow)

Note that starting in R2021b you can use a different syntax for plotting data in a table:

yyaxis left
scatter(dec22LN2testingPROCESSEDS2,'DelTmin','OutletK')
yyaxis right
scatter(dec22LN2testingPROCESSEDS2,'DelTmin','MassFlow')

[Yulia Gitter]

Oh thank you so much for all the help! I am still in the process fo learning matlab. I really appreciate it!