How to draw a surface from scattered data in Scilab?

How can I plot such a thing shown in the Fig with Scilab.

For example, There is a value of coupling loss at the location of (X,Y). So, there is a certain Z value for each (X, Y) points but the value is not a function of this (X,Y).

Any help is appreciated.

I expect it to be look exactly like in this figure, or 3D surface plot as.

For unstructured data like this one (z as an unknown function of scattered (x,y) data) the only way is to use a triangulation of (x,y) data and plot resulting triangles in the 3d space, like in this example

x=rand(50,1);
y=rand(50,1);
z=rand(50,1);
tri = mesh2d(x, y);
gcf().color_map=parulacolormap(128);
plot3d1(x(tri),y(tri),z(tri));
gce().hiddencolor=0;