assign specific colors to data in plot

I am trying to assign to a scatter graph 3 specific colors,

I created an array with an assigned value (1,2 and 3) for each color, and it sort of worked, only that the colors selected were not my choice. I want my colors to be green, red and blue, and so far I cant figure out how to do it.

here's the code:

scatter(pressure,temperature,150,color_2,'filled')

color_2 is an array of numbers (e.g. 1, 1, 1, 3, 2, 3, 2, 3, etc..)

as you can see below, it works, only that the colors were not the colors of my choice...

a follow up question: I want to create a legend of my selected colors, and I cant figure that out as well

thanks,

Amir

Answer 1

[Walter Roberson]

cmap = [0 1 0; 1 0 0; 0 0 1];
cdata = cmap(color_2, :);
scatter(pressure, temperature, 150, cdata, 'filled')

or

cmap = [0 1 0; 1 0 0; 0 0 1];
scatter(pressure, temperature, 150, color_2, 'filled')
colormap(cmap)

[Amir Topaz]

it works, thanks a lot!

can you help me with my second question?

I want to add legend that will contain the different colors and each color with a specific category

for example:

red circle - 'monday'

green circle - 'tuesday'

blue circle - 'wednesday'

[Walter Roberson]

names = {'monday', 'tuesday', 'wednesday'};
for K = 1 : length(names)
    SH(K) = scatter(nan, nan, 15, cmap(K,:));
end
legend(SH, names)

[Amir Topaz]

I get the following error:

Error using legend (line 261)

Invalid argument. Type 'help legend' for more information.

[Walter Roberson]

You did not have "hold on"

cmap = [0 1 0; 1 0 0; 0 0 1];

hold on
names = {'monday', 'tuesday', 'wednesday'};
for K = 1 : length(names)
    SH(K) = scatter(nan, nan, 15, cmap(K,:));
end
legend(SH, names)

[Amir Topaz]

true.

thanks a lot, problem solved