How to plot a polar plot from a matrix or excel file ?

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Anshuman S
Anshuman S el 12 de Oct. de 2018
Comentada: Walter Roberson el 12 de Oct. de 2018
I have a matrix A which contains values at different angles & radius. The index of this matrix represents ( angles,radius ) as (i,j) . Now how to plot these values on a polar plot ? I also want to make a contour plot for these values in polar co-ordinate .
Let the matrix be test file ( analytical.csv) attached with this document. It contains 5 columns and 4 rows , colums represent different radius = ( 0 , 0.25, 0.50 , 0.75 , 1 ) and rows represent different angles = ( 0 , pi/2 , pi , 3pi/2 ) respectively.
Thanks
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Anshuman S
Anshuman S el 12 de Oct. de 2018
take m = 4 and n = 5

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Respuestas (2)

KSSV
KSSV el 12 de Oct. de 2018
[A,txt,raw] = xlsread('C:\Users\srinivas\Downloads\analytical.csv') ;
r = [ 0 , 0.25, 0.50 , 0.75 , 1] ;
th = [ 0 , pi/2 , pi , 3*pi/2 ] ;
[R,T] = meshgrid(r,th) ;
% Create polar data
% Convert to Cartesian
X = R.*cos(T);
Y = R.*sin(T);
h = polar(X,Y);
hold on;
contourf(X,Y,A);
% Hide the POLAR function data and leave annotations
set(h,'Visible','off')
% Turn off axes and set square aspect ratio
axis off
axis image
  5 comentarios
Anshuman S
Anshuman S el 12 de Oct. de 2018
Walter , May you please help me with this !
Walter Roberson
Walter Roberson el 12 de Oct. de 2018
You have chosen to replace Mathwork's plot.m with your own. Because plot() is called in many places in MATLAB, you will need to upgrade your plot.m to handle all of those cases, which will take a lot of work.
What is it that you are extending plot() to be able to handle that it does not handle already ?
Because a partly-completed plot.m is likely to interfere with your use of MATLAB until you have completely finished your fully-compatible extension or replacement of plot(), we would recommend that you name your plot.m by some other name while you work through the development stages.
... We are not sure what any of this has to do with the task of drawing a contour plot of that matrix. Why not use the regular contour() call to do that instead of developing a complete replacement for plot() ?

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Image Analyst
Image Analyst el 12 de Oct. de 2018
Do not call your m-file plot.m. Call it myPlot.m or something like that. Obviously change the name inside the file too.

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