Lines on 3D surface plot

Hello, I have the following example (see below) of a data that I am using to plot a 3D surface. What I would like to do is to show on my surface the intersection lines of horizontal planes parallel to xy plane with my surface. These parallel planes could be for example at z= 210, z=220, z=230, z=240 etc (intervals could be regular or not). Could you please let me know whether I can do this and how? The data and what I have done so far is here:

X =[

           0         0         0         0         0         0         0         0         0         0
      0.0357    0.0357    0.0358    0.0358    0.0359    0.0359    0.0359    0.0360    0.0360    0.0360
      0.0714    0.0715    0.0716    0.0716    0.0717    0.0718    0.0719    0.0719    0.0720    0.0721
      0.1071    0.1072    0.1074    0.1075    0.1076    0.1077    0.1078    0.1079    0.1080    0.1081
      0.1429    0.1430    0.1431    0.1433    0.1434    0.1436    0.1437    0.1439    0.1440    0.1441];
  Y=[

      3.5714    3.5750    3.5786    3.5821    3.5857    3.5893    3.5929    3.5964    3.6000    3.6036
      3.5357    3.5392    3.5428    3.5463    3.5499    3.5534    3.5569    3.5605    3.5640    3.5675
      3.5000    3.5035    3.5070    3.5105    3.5140    3.5175    3.5210    3.5245    3.5280    3.5315
      3.4643    3.4677    3.4712    3.4747    3.4781    3.4816    3.4851    3.4885    3.4920    3.4955
      3.4286    3.4320    3.4354    3.4389    3.4423    3.4457    3.4491    3.4526    3.4560    3.4594];
  Z =[

    276.7398  270.9391  265.1383  259.3376  253.5368  247.7361  241.9354  236.1346  230.3339  224.5331
    272.3587  266.5536  260.7484  254.9433  249.1382  243.3331  237.5279  231.7228  225.9177  220.2644
    267.9776  262.1680  256.3585  250.5490  244.7395  238.9300  233.1205  227.3110  221.5015  216.3515
    263.5964  257.7825  251.9686  246.1548  240.3409  234.5270  228.7131  222.8992  217.0853  212.4386
    259.2153  253.3970  247.5788  241.7605  235.9422  230.1240  224.3057  218.4874  212.6691  208.5257];

figure
surf(X,Y,Z)
s=surf(X,Y,Z,'EdgeColor','none')

xlabel('Wi');
ylabel('So');
zlabel('SD');

%%Extract X,Y and Z data from surface plot

x=s.XData;
y=s.YData;
z=s.ZData;

Thanks. K.

Answer 1

[Star Strider]

I am not certain exactly what you want.

This should at least get you started:

figure
surf(X,Y,Z)
s=surf(X,Y,Z,'EdgeColor','none')
hold on
for k1 = 210:10:270
    surf(X, Y, k1*ones(size(Z)), 'FaceAlpha',0.5, 'EdgeColor',[1 1 1 ]*0.8)
end
hold off

It simply loops, creating a horizontal plane of ones at each value of ‘k1’.

If you want a larger plane, you will have to define new ‘X’ and ‘Y’ matrices for it. The ‘Z’ matrix defining the plane would then be a ones matrix the same size as those matrices.

[Katerina F]

Hello, Thanks. I will explain a bit more. I do not want to draw the horizontal planes. What I want to draw is only the intersection lines of these planes with my surface (that is, to look like horizontal grid lines on my surface, which will follow the curve of the surface). I am not sure how to do it.

[Star Strider]

The contour3 function will do what I believe you want:

figure
surf(X,Y,Z,'EdgeColor','none')
hold on
contour3(X, Y, Z, [ 210:10:270], 'LineWidth',1, 'Color','k')
hold off

Experiment with 'LineWidth' and 'Color' to get the result you want.

[Akhil Kallepalli]

If you had an image file where X, Y are the coordinates of the pixel and Z is the value of the pixel, how would this implementation change?

Answer 2

[John BG]

Hi Katerina

this is John BG <mailto:[e-mail] [e-mail]>

I have answered your surface 'sectioning' with vertical planes answering your other question.

https://uk.mathworks.com/matlabcentral/answers/351722-how-to-update-matrix

if you find this answer useful would you please be so kind to consider marking my answer as Accepted Answer?

To any other reader, if you find this answer useful please consider clicking on the thumbs-up vote link

thanks in advance

John BG

<mailto:[e-mail] [e-mail]>

[Jan]

This message contains only a link to a completely unrelated thread of another user, 4 times the name of the author and begging for points.