How do i interpolate a large matrix of data thats not in ascending order?

I have a large matrix of data that consists of the first column containing a variety of different depth values, that are not out of ascending order, and the second column contains a number of corresponding salinity values. How would i be able to interpolate the data so that i have a value for every 50 metres? The shallowest depth is 125 metres and the deepest depth is around 1500 metres,

Answer 1

[Ahmed A. Selman]

There are few interpolation techniques in Matlab. You can start with the functions

interp1q % for simple 1-D interpolation, OR
interpft % for 1-D interpolation with Fast Fourier Transform

Simple user tools such as (cftool) - Curve Fitting Tool, may also help finding interpolated data after finding a fitting equation to your physical system.