# Problem with Plot 3D

조회 수: 4(최근 30일)
ragnor 2021년 7월 19일
댓글: ragnor 2021년 7월 23일
Hello Matlab Community,
I am trying to plot a 3D coloured with some data, however the plot is looking a bit different. The negative and positive values in the Z matrix are identical only difference is the sign. But the plot doesnt look identical in the negative and positive axis. It would be great if someone could help me with this.
x = data(:,1:3);
x = table2array(x);
t = data(:,4);
t = table2array(t);
X = x(:,1);
Y = x(:,3);
Z = t;
N = 200 ;
x = linspace(min(X),max(X),N) ;
y = linspace(min(Y),max(Y),N) ;
[Xi,Yi] = meshgrid(x,y) ;
Zi = griddata(X,Y,Z,Xi,Yi) ;
surf(Xi,Yi,Zi)
##### 댓글 수: 2표시숨기기 이전 댓글 수: 1
ragnor 2021년 7월 23일
Hello Mr. Rik
I have added the excel sheet back, it was just a silly recording mistake and the corrected file is already uploaded by the person who answered the question.
Also, thanks for you valuable advice. Will keep it mind.
Regards

댓글을 달려면 로그인하십시오.

### 채택된 답변

Cris LaPierre 2021년 7월 19일
편집: Cris LaPierre 2021년 7월 19일
It looks like, in your Excel sheet, you have erroneously recorded all Y values of -7 as 7. That could explain part of the issue.
Once that is done, you might quickly view the results with the following code.
data.Properties.VariableNames = ["X","F_sw","Y","Z"];
% order the data
data = sortrows(data,["X","Y"]);
X = unique(data.X);
Y = unique(data.Y);
Z = reshape(data.Z,[length(Y),length(X)]);
% View
figure
surf(X,Y,Z)
##### 댓글 수: 3표시숨기기 이전 댓글 수: 2
Cris LaPierre 2021년 7월 20일
Legend items correspond to plot objects. If you want two items in your legend, you need two distinct objects in your axes. You currently have one, a surface. Create your surface using surf, and add a second object for your markers, perhaps using scatter, and then you can create a legend with 2 items in it.
Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.
data.Properties.VariableNames = ["X","F_sw","Y","Z"];
% order the data
data = sortrows(data,["X","Y"]);
X = unique(data.X);
Y = unique(data.Y);
Z = reshape(data.Z,[length(Y),length(X)]);
% View
figure(1)
scatter3(data.X,data.Y,data.Z,12,[1 0 0],"filled","MarkerEdgeColor",[0 0 0])
hold on
s = surf(X,Y,Z,"FaceColor",[0.784 0.816 0.831]);
hold off
ylabel('Phase Current (A)',"FontSize",10,"FontWeight","normal");
zlabel('Error Voltage (V)',"FontSize",10,"FontWeight","normal");
title('title','FontSize',10,'fontweight', 'normal');
legend("Label 1","Label 2")

댓글을 달려면 로그인하십시오.

R2020a

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by