Create surface plot from txt file with x y z coordinates.
26 views (last 30 days)
Show older comments
I am trying to plot a 3D surface from the x y and z coordinates that I obtain in a txt file with three columns representing x, y and z values.
I can extract the x, y and z values and create 3 seperate column matrix and then I try to plot the x, y and z using the surf function but it returns an error stating - "Z must be a matrix, not a scalar or vector". However it plots correctly if I use the command plot3(x,y,z) but it does not creates a surface and also in plot3 z has no negative values.
I will insert the code here,
clear all;
close all;
clc
A=dlmread('mode shape 1.txt');
x=A(:,1);
y=A(:,2);
[X,Y]=meshgrid(x,y);
Z=A(:,3);
surf(X,Y,Z)
1 Comment
Answers (1)
Sayan
on 30 Aug 2023
I understand that a 3D surface plot needs to be plotted from the x, y, and z coordinates extracted from the text file. However, here creating a "meshgrid" is not required. Only plotting the x, y, and z data with the "surf" function will work. "Z" is just a column vector whereas "X" and "Y" are matrices with size equal to the product between the "length(y)" and "length(x)". It can be plotted as shown below.
A=dlmread('mode shape 1.txt');
x=A(:,1);
y=A(:,2);
z=A(:,3);
surf(x,y,z)
For further assistance with the "surf" and "meshgrid" functions you can refer to the following MATLAB documentation:
- https://in.mathworks.com/help/releases/R2019b/matlab/ref/surf.html
- https://in.mathworks.com/help/releases/R2019b/matlab/ref/meshgrid.html
Hope this helps in resolving the issue.
0 Comments
See Also
Categories
Find more on Surface and Mesh Plots 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!