How to plot peaks on desired location in a 3D plot?

There are two vectors that will make an xy-plane. I want to draw a peak pointing in z-direction on a desired location on the xy-plane. In code form it is:

x=linspace(0,180,100);% 1st vector
y=x;% 2nd vector

Now I want to draw a peak of strenght 5 on the intersection of the point (x1,y1)=(30,50).Likewise, I want to draw another peak on the intersection of the point (x2,y2)=(40,120). Further, I want to draw another peak on the intersection of the point (x3,y3)=(60,140). But this whole plot should be a 3D plot as shown in the attached image.

[Matt J]

What determines the z-valeus everywhere where there isn't a peak?

[Sadiq Akbar]

Thank you for your response. There is no eq. but I want to draw peaks of my desired values. Say for example, one peak should be of height 5, another should be of height 5.5 and another should be of height 7.

Answer 1

[Star Strider]

[X,Y] = ndgrid(0:300);
C = 50:100:300;
Zf = @(C) exp(-(((X-C).^2)*0.5+((Y-C).^2)));
Z = Zf(C(1)) + Zf(C(2)) + Zf(C(3));

[pks,locs] = findpeaks(Z(:), 'MinPeakHeight',0.5)

pks = 3×1

1 1 1

locs = 3×1

15101 45301 75501

figure
surf(X, Y, Z, 'EdgeColor','none')
hold on
plot3(X(locs), Y(locs), Z(locs), '^r')
hold off

Experiment with your data with this approach.

.

[Sadiq Akbar]

Thank you very much dear Star Strider for your response. Indeed I want like this but here you have used some function for z and in my case I have no function but just a vector like z=[1.2e-8 3.5e-7 7.1e-9] and I want to draw a line for its 1st element (i.e., 1.2e-8) on a point (x1,y1)=(30,50) located on xy-plane similar to yours or similar to the one in the attached image. Likewise, I want to draw another line on another point (x2,y2)=(70,120) on xy-plane for the 2nd element of vector z(i.e., 3.5e-7). And in the same fashion I want to draw another line for the 3rd element of vector z(i.e., 7.1e-9) on a point (110,210) on xy-plane.

[Star Strider]

I cannot understand that.

Where do each one of the lines start and end?

Are the lines supposed to be vertical, and from 0 through each peak?

(The surf or surfc function plots a matrix. How that matrix is created it not relevant.)

[Sadiq Akbar]

Thank you very much dear Star Strider. The line will start from just the xy-plane as you have done in your code or as in attached image.Yes, these lines will be vertical as in atached image above. Yes, you are right that surf and surfc functions plot a matrix and I don't have matrix. That's the problem, so I asked it here.

[Star Strider]

I do not understand that you don’t have the matrix.

To just plot the points as lines use the stem3 function, with the surfc plot, or by itself.

x1y1 = [ 30  50 1.2E-8];
x2y2 = [ 70 120 3.5E-7];
x3y3 = [110 210 1.7E-9];
xymtx = [x1y1; x2y2; x3y3];                             % Concatenate Into Vector

figure
stem3(xymtx(:,1), xymtx(:,2), xymtx (:,3), 'Marker','none', 'LineWidth',2)
grid on
set(gca, 'ZScale','log')                                % Logarithmic Z-Axis ()ptional)

Use the hold function to add the lines to the surfc plot.

Change the properties of the stem3 plot to get the desired result.

.

[Sadiq Akbar]

I am extremely sorry for bein late.Thank you very much dear Star Strider for your help. Indeed I want like this.But in given plot the limits of x and y-axes are different while I want their limits the same i.e., limits of both of them must be from 0 to 180. Can we do this change in given figure while keeping all the three lines plots undisturbed? Further, I am not getting it: "Use the hold function to add the lines to the surfc plot". What do you mean by this?

[Star Strider]

The axes ranges can be limited —

x1y1 = [ 30  50 1.2E-8];
x2y2 = [ 70 120 3.5E-7];
x3y3 = [110 210 1.7E-9];
xymtx = [x1y1; x2y2; x3y3];                             % Concatenate Into Vector

figure
stem3(xymtx(:,1), xymtx(:,2), xymtx (:,3), 'Marker','none', 'LineWidth',2)
grid on
set(gca, 'ZScale','log')                                % Logarithmic Z-Axis (Optional)
xlim([0 180])
ylim([0 180])

However, with the axes limited this way, ‘x3y3’ is no longer visible because it plots beyond the limits.

.

[Sadiq Akbar]

Thank you very much dear Star Strider for your help.

[Star Strider]

As always, my pleasure!