How can I produce different colours for different clusters?

Hi,

I have the following dataset --> three columns (x,y, class of the data point(0,1,2,3 or 4)).

(-9.69171, -8.86384, 0)

(-9.55902, -8.10946, 0)

(-1.73544, -7.12043, 1)

(-1.77755, -6.39318, 1)

(-3.79288, -5.00445, 2)

(-3.36182, -6.39692, 2)

(-1.46405, -1.70081, 3)

(-0.413965, -2.22041, 3)

(-9.59192, -8.78982, 4)

(-9.72115, -8.37142, 4)

(This is just a sample dataset)

How can I plot that dataset where each data point has the same colour of its label. (The data is labelled in four groups).

Thank you

Answer 1

[Walter Roberson]

pointsize = 30;
scatter(x(:), y(:), pointsize, group_number+1);
colormap(jet(5))

[Abdulatif Alabdulatif]

I did not catch you answer because I am not very familiar with Matlab.

The matrix name: sample

size: 217 rows and 3 columns (x,y,class value)

How can I implement your commands, do I need to write it as a function or just paste it in a command line one by one.

Take into consideration that I want all points in the same plot with different colour for each class.

Thanks

[Walter Roberson]

pointsize = 30;
scatter(sample(:,1), sample(:,2), pointsize, sample(:,3)+1);
colormap(jet(5))

The sample(:,3)+1 will give the colormap index to use -- so use color #1 for group 0, color #2 for group 1, and so on. And then the colormap(jet(5)) tells it to use 5 different colors in the colormap, so each of those 5 groups will get colored distinctly.

[Abdulatif Alabdulatif]

Perfect!

One more question: Is it possible to use different symbols (+, * , -) for each class?

Thanks a lot for your support

[Walter Roberson]

You would need to use separate scatter() calls for each class. Any one call to scatter() can only use one symbol.

[Abdulatif Alabdulatif]

Great!

1- How can I plot from 1 to 100 in separate scatter with a specific symbol?

Thanks

[Walter Roberson]

symbols = {'*', '+', '.', 'v', 'p'};

for idx = 1 : length(symbols)
  mask = group_number == idx;
  scatter(x(mask), y(mask), pointsize, 'Marker', symbols{idx});
  hold on
end