MATLAB: How to retrieve z value from surf plot given x and y

MATLAB and Simulink Student Suiteplotsurf

I got a surface useing:

s= surf(X, Y, Z)

Since the X, Y, and Z are discrete, I want to get the consecutive value of Z. For example, the origin data X and Y are all integers, and I don't the relationship between XY and Z, I want to get the z value where X = 1.87 and Y = 2.9. Is it possible? What should I do?

Best Answer

Interpolate with INTERP2 : https://www.mathworks.com/help/matlab/ref/interp2.html

where Xq and Yq are defined using the values given in your question.

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MATLAB: How to Plot Grid on a Scatter Plot

Depending on the result you want, here are some options to experiment with:

[x,y,z] = sphere;      %# Makes a 21-by-21 point sphere
x = x(11:end,:);       %# Keep top 11 x points
y = y(11:end,:);       %# Keep top 11 y points
z = z(11:end,:);       %# Keep top 11 z points
r = 1;                 %# A radius value
figure
scatter3(r.*x(:),r.*y(:),r.*z(:), 0.001+z(:)*100, 'o', 'filled');  %# Plot the surface

hold on
mesh(x,y,z, 'EdgeColor','k', 'LineStyle','-')
hold off
axis equal;            %# Make the scaling on the x, y, and z axes equal

figure
mesh(x,y,z, 'EdgeColor','k', 'LineStyle',':', 'FaceAlpha',0.1)
hold on
scatter3(r.*x(:),r.*y(:),r.*z(:), 0.001+z(:)*100, 'o', 'filled');  %# Plot the surface
hold off
axis equal;            %# Make the scaling on the x, y, and z axes equal

MATLAB: Plot3(X,Y,Z)

With plot3, you do not have to use meshgrid. Just create a vector a X values, a vector of Y values, and compute your Z values from the equation.

Whether grid needs to be on or off is up to whomever is grading your assignment. When it is on, it adds a grid to the axes. It does not affect how the plot behaves, just it's appearance.

Best Answer

Related Solutions

MATLAB: How to Plot Grid on a Scatter Plot

MATLAB: Plot3(X,Y,Z)

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