3d plots with attributes of points
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BERNARDO CHIARAVALLI
on 20 Nov 2024 at 16:15
Commented: BERNARDO CHIARAVALLI
on 22 Nov 2024 at 14:48
Good evening,
I built in matlab a sets of 3d points with same x and y coordinates and different z and I have used tham in another program wich calculate in those positions some variables (speed and direction of fluid). These points are organized in 12 matrix in wich x and y remain the same, while z varies (with depth).
I want to built a script to represent them and colour them by the value of speed and direction. I read about plot3 whic take in imput 3 vectors and display them in 3d space but I don't know how to afficiently connect the 3d coordinates with attributes.
Can you please give me some advice?
Thank you very much
4 Comments
Jacob Mathew
on 21 Nov 2024 at 3:48
Hey BERNARDO,
You can add columns that represent the color as well as other properties to the matrix that has the coordianates. The column values can be based on your calculation of speed and direction or other parameters as well. This can then be passed to plotting functions like scatter3 which will plot them with the respective color.
An example dataset and plotting is as follows:
% Initialize matrix with 12 rows and 4 columns
data = zeros(12, 4);
% Generate data points with x = y
for i = 1:12
x = i; % x and y are the same
y = i;
z = rand(); % Random z coordinate
color = i; % Unique color for each point
% Assign values to the matrix
data(i, :) = [x, y, z, color];
end
% Plot the points using scatter3
figure;
scatter3(data(:, 1), data(:, 2), data(:, 3), 100, data(:, 4), 'filled');
% Label the axes
xlabel('X Axis');
ylabel('Y Axis');
zlabel('Z Axis');
title('3D Scatter Plot with Unique Colors');
grid on;
Answers (1)
KSSV
on 21 Nov 2024 at 5:49
Let data be your three columns matrix.
x = data(:,1) ;
y = data(:,2) ;
z = sata(:,3) ;
% Plot as unstructured grid
dt = delaunayTriangulation(x,y) ;
p = dt.Points ;
tri = dt.ConnectivityList ;
F = scatteredInterpolant(x,y,z) ;
z = F(p(:,1),p(:,2)) ;
figure(1)
trisurf(tri,p(:,1),p(:,2),z)
view(2)
shading interp
% Plot as structured grid
xi = linspace(min(x),max(x),300) ;
yi = linspace(min(y),max(y),300) ;
[X,Y] = meshgrid(xi,yi) ;
Z = griddata(x,y,z,X,Y) ;
figure(2)
pcolor(X,Y,Z) ;
shading interp
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