How to interpolate values

Hello. I have the question about how would you interpolate some values. For example, I have:

x      y       z
1      4       7 
3      6       9

I want a point between (1,4) and (3,6) with the mean value of z.

Thank you in advanced!!

[Jan]

This is not clear. What is "a point between (1,4) and (3,6)"?

[chaos4u2]

I mean for example a middle point between (1,4) and (3,6), that would be (2,5). How can I do the interpolation?

[Matt Kindig]

Do you just mean that you want the mean of the x, y, and z coordinates? If so, your middle point would simply be

mid = mean([x, y, z], 1);

Or are you asking something else?

[chaos4u2]

Thank your for answering.

Not exactly. I have a file .dat of coordinates x,y,z. About 2 million data or even more.

What I want is to reduce all, for example at 10.000. But I don't know how to do it. I thought to do an interpolation, but I'm realising that's not a good idea.

Answer 1

[Sean de Wolski]

There aren't enough points to perform a 2d scattered interpolation which requires a Delaunay Triangulation under the hood. Instead, just use interp1 twice:

 interp1([1 4],[7 9],2.5)

or acquire more data (recommended).

[chaos4u2]

Thank you!!!