Need help to create MATLAB program for Nearest Neighbor Interpolation

I need help to create MATLAB program to interpolate temperature data given as input.

Input data contains temperature for given latitude and longitude for particular year and month.

Input file is in excel format.

Format for interpolation input File:

1st column - year

2nd column - month

3rd column - latitude

4th column - longitude

5th column - value

Data is like below,

1969 1 17.5 72.5 25

1969 2 17.5 72.5 27

1969 3 17.5 72.5 29

.

.

.

2005 11 20.0 72.5 22

2005 12 20.0 7 2.5 24

Data is for range 1969/01 to 2005/12.

For co-ordinates 17.5N - 72.5E, 20.5N - 72.5E

Temperature data is in nonlinear format.

Need to interpolate using 0.25 x 0.25.

so, Now need to find temperature for 18.25N - 72.5E, 18.50N - 72.5E, 18.75N - 72.5E ...

Output file should contain temperature for above mentioned latitude and longitude and in excel format.

Can anybody help me on this issue.

[Adam Danz]

Use interp1() with 'nearest' method. (click link for description).