how to plot a color-coded matrix
11 views (last 30 days)
Show older comments
Hello
I have a matrix of data including 3 column,for example:
a=[1 0 3;1 1 4;1 2 4;1 3 5]
x=a(:,1);y=a(:,2);z=a(:,3);
1) in my real data, z is the value associated with (x,y). so I would like to have a 2D chart with x and y value being color-coded based on z value. like all the points in the chart with 1<z<2 are red and 2<z>3 are blue and etc. is there a way to do that?
2) to get what i want, I used the below command for a sample matrix with different z value but the chart is just giving me all points in blue color. what am i missing? what is the best syntax for what I want?
figure
scatter3(x(0<z<=2),y(0<z<=2),z(0<z<=2),'g.')
hold on
scatter3(x(2<z<=4),y(2<z<=4),z(2<z<=4),'k.')
hold on
scatter3(x(4<z<=6),y(4<z<=6),z(4<z<=6),'r.')
Thank you !
0 Comments
Accepted Answer
Star Strider
on 19 Jun 2018
Try this:
a=[1 0 3;1 1 4;1 2 4;1 3 5]
x=a(:,1);
y=a(:,2);
z=a(:,3);
L1 = (z > 1) & (z <= 3); % Logical Subscripts For Condittion #1
L2 = (z > 3) & (z <= 5); % Logical Subscripts For Condittion #2
figure(1)
scatter3(x(L1), y(L1), z(L1), 'rp')
hold on
scatter3(x(L2), y(L2), z(L2), 'bp')
hold off
grid on
Change the conditions as necessary for your data.
3 Comments
Star Strider
on 19 Jun 2018
As always, my pleasure!
Using legend may be more practical:
legend('0 - 100', '100 - 200')
If you want to use colorbar, try this (after your scatter3 call):
colormap([1 0 0; 0 0 1])
colorbar('Ticks', [0 0.5 1], 'TickLabels',[0 100 200])
This worked when I tested it (in R2018a). You may have to experiment with it.
More Answers (0)
See Also
Categories
Find more on Colormaps in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!