Data Reshape for Contour Plot

Question

Steffen B. 2024-9-20

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2154195-data-reshape-for-contour-plot

评论： KSSV 2024-9-20

Hello,

I'm facing a few problems while data reshaping. I have velocity values in a cartesian coordinate system (x,y,z) . The values are at the surface of a cylinder with a defined radius.

Therefore a transformation into cylinder coordinates to plot the data as 2D contour (Angle and Height) is suitable.

My Problem is that I have all the necessary data in the file 'TransformedData.txt' but it is not the required format for contourf.

I tried to reshape the data inspired by this post: (https://de.mathworks.com/matlabcentral/answers/421043-contour-plot-based-on-xyz-data) but it's still not working.

clc,close all
clearvars
filename='RawDataCFXPost.xlsx';
% Data Transformation
x=xlsread(filename,'A3:A36003');% Cartesian Coordinate x
y=xlsread(filename,'B3:B36003');% Cartesian Coordinate y
z=xlsread(filename,'C3:C36003');% Cartesian Coordinate z
ZData=xlsread(filename,'D3:D36003');% Velocity Value v
[theta,rho,z] = cart2pol(x,y,z);% Coordinate Transformation from Cartesian to Clyinder Coordinate System
A=[theta,rho,z,ZData];% Array with Transformed Data
writematrix(A,'TransformedData.txt','Delimiter',' ');  
type TransformedData.txt;
% Data Reshape
Data = load('TransformedData.txt');
[Du,D1] = unique(Data(:,1));
Dd = diff(D1);
DataNew = reshape(Data, Dd(1), [], size(Data,2));
Angle = DataNew(:,:,1);
Height = DataNew(:,:,3);
Velocity = DataNew(:,:,4);
% Contour Plot
figure
contourf(Angle, Height, Velocity)