problem with colorbar in using scatter3

Hi. I have a table called "damage" with four collumns "wind", "I", "derate", "Index4". I am using the following code to plot "Index4" vs. "wind", "I" and "derate":

s = scatter3(damage,'wind','I','derate','filled','ColorVariable','Index4'); s.SizeData = 100;colorbar

but I get the following error:

Error using scatter3 (line 57)

Color must be one RGB triplet, an m-by-3 matrix of RGB triplets with one color per scatter point, or an m-by-1 vector with one

value per scatter point.

Any feedback is very much appreciated.

[Joe Vinciguerra]

Please attach a .mat file of your table

[Farid Khazaeli Moghadam]

.mat file is attached now

Answer 1

[Cris LaPierre]

First, the error is not related to colorbar. It is an error occurring with scatter3, specifically the format of your ColorVariable.

It looks like you found this example in the doc: https://www.mathworks.com/help/matlab/ref/scatter3.html#mw_980777c0-abb7-4053-b084-6da6cc75c25a

I can duplicate the error by making Index4 anything but what is expected (indicated in the error message). The fix is to make Index4 one of the accepted inputs (described here: https://www.mathworks.com/help/matlab/ref/scatter3.html#mw_0ec595ed-40a4-4191-be63-534236f0fb9e)

% How I can recreate the error message: Index4 is not mx3, 1x3, nor mx1
wind = [30 40 50]';
I = [1 2 3]';
derate = [5 6 5]';
Index4 = [1 3 7;2 5 9]';
damage = table(wind,I,derate,Index4)

damage = 3×4 table
    wind    I    derate    Index4
    ____    _    ______    ______

     30     1      5       1    2
     40     2      6       3    5
     50     3      5       7    9

s = scatter3(damage,'wind','I','derate','filled','ColorVariable','Index4'); 

Error using scatter3
Color must be one RGB triplet, an m-by-3 matrix of RGB triplets with one color per scatter point, or an m-by-1 vector with one value per scatter point.

s.SizeData = 100;
colorbar

[Farid Khazaeli Moghadam]

These four variables are four time series of the same length. I plan to picturize it by a 4D plot. I use colormap to show the forth diemension. Yeah the error looks to be with the format of ColorVariable but not sure about a proper way to define this variable. My problem looks very similar to what here

https://www.mathworks.com/help/matlab/ref/scatter3.html#mw_980777c0-abb7-4053-b084-6da6cc75c25a

[Cris LaPierre]

That's the same example I linked to, so glad we are agreed.

It looks like the issue is you have some complex numbers in Index4. Consider using the magnitude of your values to specify color. If the values should not be complex, check how Index4 is calculated.

load matlabFarid.mat
damage.Index4 = abs(damage.Index4)

damage = 1000×4 table
    wind    I    derate      Index4  
    ____    _    ______    __________

     4      0       0      3.2381e-06
     4      0      10       3.806e-06
     4      0      20       3.806e-06
     4      0      30       3.806e-06
     4      0      40      3.8062e-06
     4      0      50      3.8057e-06
     4      0      60      3.8062e-06
     4      0      70      3.8057e-06
     4      0      80      3.8059e-06
     4      0      90      3.8059e-06
     4      0     100       3.806e-06
     4      4       0      3.2384e-06
     4      4      10      3.7961e-06
     4      4      20      3.7951e-06
     4      4      30       3.797e-06
     4      4      40      3.7961e-06

s = scatter3(damage,'wind','I','derate','filled','ColorVariable','Index4'); 
s.SizeData = 100;
colorbar

[Farid Khazaeli Moghadam]

You are right. Thanks so much.