put me out of my misery
조회 수: 3 (최근 30일)
이전 댓글 표시
i have 3 matrices..
x = 1 * 264;
y = 1* 264;
z = 1 * 264;
contour(x,y,z) % error z must be 2* 2 or more
hence i did
[X,Y] = meshgrid(x,y); Z =griddata(x,y,z,X,Y);
contour(X,Y,Z) is giving some weird plot. Not desirable.
Now how to do it...
댓글 수: 2
Iain
2014년 1월 31일
What are you trying to plot?
contour(x,y,z) is expecting x to be a vector with n elements, y a vector with m elements, and z to be n by m (or is it m by n)
채택된 답변
Bjorn Gustavsson
2014년 1월 31일
편집: Bjorn Gustavsson
2014년 1월 31일
qwe = xlsread('yourfile.xls');
scatter(qwe(:,1).*cos(qwe(:,2)*pi/180),...
qwe(:,1).*sin(qwe(:,2)*pi/180),15,...
(qwe(:,3)-min(qwe(:,3)))*5+5,'filled')
So there you see some odd spots (sensor faulty or something?). At least easy to reinterpolate outside that region:
X = 24.7:0.1:27;
Y = 0:0.1:5;
[X,Y] = meshgrid(X,Y);
Z = griddata(qwe(:,1).*cos(qwe(:,2)*pi/180),...
qwe(:,1).*sin(qwe(:,2)*pi/180),qwe(:,3),X,Y);
% Or any of the newer variants like Walter suggested.
% do the contour:
hold on
contour(X,Y,Z,1.25:0.025:max(qwe(:,3)),'b')
HTH
댓글 수: 2
Bjorn Gustavsson
2014년 2월 3일
Yes, the trigonometric functions work on radians. You'd be better off learning to use radians.
추가 답변 (3개)
Mischa Kim
2014년 1월 31일
Rizwana, first option works just fine. Make sure that Z is an mxn matrix, where m and n are the length of the two vectors x and y. meshgrid , e.g., generates an appropriate grid.
x = rand(10,1);
y = rand(10,1);
[X,Y] = meshgrid(x,y);
Z = sin(X)+cos(X+Y);
figure
contour(X,Y,Z)
or see the documentation.
댓글 수: 3
Mischa Kim
2014년 1월 31일
The contour plot is more of a 3D type plot, where the dependent variable (Z) depends on two variables (X, Y). So it is not quite clear to me what you would like to achieve.
Iain
2014년 1월 31일
편집: Iain
2014년 1월 31일
Looks like you actually want: plotyy or subplots:
plotyy(x,y,x,z) % plot angle against radius on the left hand y axis, and pressure against radius on the right hand y axis.
subplot(211)
plot(x,y)
subplot(212)
plot(x,z)
or
subplot(121)
plot(x,y)
subplot(122)
plot(x,z)
obviously, switch the x,y,z's around to plot against what you want to. - contour plots are only valid for 2-D signals, and you've only got 3 1D signals.
댓글 수: 3
Iain
2014년 1월 31일
Is circumferential pressure supposed to be a function of angle and radius?
If radius has "n" elements, and you have "m" angles, then you should get "n x m" pressures, and not have all three as being vectors.
For example, with a trivial function I know is wrong:
x= 0:0.1:1;
y= 0:36:360;
z = x' * y;
contour(x,y,z)
would work.
Walter Roberson
2014년 1월 31일
댓글 수: 7
Walter Roberson
2014년 1월 31일
It appears that TriScatteredInterp appeared in R2009a. griddata() does exist in your release though.
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