Plotting multilines with multi colours

I have a very big matrix called Vertices (100000 X 6 matrix) First 3 columns have x y z points. last 3 columns have the colour of that point. for eg first 2 rows are

7645   383   3    49  47  39
7649   382   4    38  37  31

I need to plot all the points with the defined colors.

for ii = 1:1000
      plot3(Vertices(ii,1), Vertices(ii,2), Vertices(ii,3), 'color',[Vertices(ii,4)/255, Vertices(ii,5)/255, Vertices(ii,6)/255], 'Marker', '.');

        hold on;
  end

This works. I have tried for first 1000 element. But since my matrix size is very large. It take a lot of time if i plot using loop. Is there any easy way to plot this?

Answer 1

[bes]

scatter3(Vertices(:,1), Vertices(:,2), Vertices(:,3),1, Vertices(:, 4:6)/255, 'filled'); % 3D scatter plot

Answer 2

[Image Analyst]

You can make this into an RGB image and then display with the image() or imshow() command. It will be much much faster that way. The only downside is that you'll have to pick a projection, like you're looking along the z axis so that you are basically looking at the x-y plane, and you won't be able to interactively rotate your 3D scatterplot of points.

[bes]

Thanks. I have used scatter3

scatter3(Vertices(:,1), Vertices(:,2), Vertices(:,3),1, Vertices(:, 4:6)/255, 'filled');

It works fine. we can rotate this 3D plot (take time to rotate because of the computer hardware limitation for large amount of points)

Answer 3

[Matt Fig]

Here is an example. If you put a tic/toc around the loop and the call to PATCH you will see that the call to PATCH is several thousand times faster. This is mainly because each call to PLOT3 creates a whole new graphics object, which takes time and memory.

% First make some data to match what you show....
[x,y] = meshgrid(-pi:.1:pi,-pi:.1:pi);
z = cos(x+y);
DAT = [x(:) y(:) z(:) round(rand(numel(x),3)*255)];  % The mx6
% Now on to the plotting.  Use two methods and compare.
% First your method.
figure('pos',[30 30 1500 900])
subplot(1,2,1)
hold

for ii = 1:numel(x)
    plot3(DAT(ii,1),DAT(ii,2),DAT(ii,3),...
          'color',DAT(ii,4:6)/255,'Marker','.');
end

title('For loop')
view(47.5,60)

% Next do it with one function call, and compare.
subplot(1,2,2)
P = patch('xdata',DAT(:,1),'ydata',DAT(:,2),'zdata',DAT(:,3),...
          'facevertexcdata',DAT(:,4:6)/255,...
          'facecolor','none','edgecolor','none',...
          'marker','.','markersize',8,...
          'markeredgecolor','flat',...
          'markerfacecolor','flat');
title('For loop')
view(47.5,60)

[bes]

Thanks a lot