Finding X Y coordinates from surface plot

[X,Y,Z] = peaks;
I=find(Z==max(max(Z)));
X(I); %x values corresponding to the points where Z is maximum
Y(I); %y values corresponding to the points where Z is maximum

To test if values are correct do

[X,Y,Z] = peaks;
surf(X,Y,Z)
hold on
I=find(Z==max(max(Z)));
plot3(X(I),Y(I),Z(I),'x')

3 个评论
显示 1更早的评论隐藏 1更早的评论

Paulo Silva 2011-4-20

She's just being a good teacher, by searching and trying to do the homework you always learn something.

Ilias Iord 2017-4-9

在 MATLAB Online 中打开

This is very helpful indeed, but I am looking for one step further:

I have two vectors of co-ordinates (1-n) for X and Y and a surface (S) with n-n corresponding values.

The question is, how can I get the X, Y values for the single minimum value of S. Because S is n-n, the above solution does not work.

%calculation of drawdown in confined aquifer
clear
clc
% Parameter and variable values
xabs=3000;
yabs=xabs;
xmin=-xabs;
ymin=-yabs;
x=xmin:50:xabs;
y=ymin:50:yabs;
x1=1500;
y1=600;
x2=700;
y2=1800;
x3=1200;
y3=900;
x4=500;
y4=800;
rw=0.3; %well radius
rinf1=2000; %m   radius of influence
rinf2=3000;
rinf3=5000;
rinf4=500;
k=2.58; %m/day
q1=1200; %m3/day
q2=1500;
q3=2000;
q4=500;
a=45; % m (confined aquifer width)
hw=30; %m ( well drawdown depth)
s1=drawdown(xabs,x1,y1,rinf1,k,q1,a);
s2=drawdown(xabs,x2,y2,rinf2,k,q2,a);
s3=drawdown(xabs,x3,y3,rinf3,k,q3,a);
s4=drawdown(xabs,x4,y4,rinf4,k,q4,a);
s=s1+s2+s3+s4;