Linear Inperpolation for missing values

Hi,

I need to find the missing values for Lat, Long in column 5 and 6 using linear interpolation. Can anybody suggest me a method in MATLAB? Excel worksheet is attached here.

Thanks in advance.

Year  Month  Day  Time  Lat  Long
1998  1  16  0  -12  42.7
1998  1  16  3    
1998  1  16  6  -12.2  42.4
1998  1  16  9    
1998  1  16  12  -13  42.1
1998  1  16  15    
1998  1  16  18  -13.8  41.9
1998  1  16  21    
1998  1  17  0  -14.6  41.5
1998  1  17  3    
1998  1  17  6  -15.4  40.4
1998  1  17  9    
1998  1  17  12  -15.9  38.9
1998  1  17  15    
1998  1  17  18  -16.1  38
1998  1  17  21    
1998  1  18  0  -16.8  37.4
1998  1  18  3    
1998  1  18  6  -17.1  36.2
1998  1  18  9    
1998  1  18  12  -17.4  35.3
1998  1  18  15    
1998  1  18  18  -18.1  35.6
1998  1  18  21    
1998  1  19  0  -18.8  35.7
1998  1  19  3    
1998  1  19  6  -19.3  34.8
1998  1  19  9    
1998  1  19  12  -19.8  34.5
1998  1  19  15    
1998  1  19  18  -20.2  34.5
1998  1  19  21    
1998  1  20  0  -21.2  34.7
1998  1  20  3    
1998  1  20  6  -22.1  34.9
1998  1  20  9    
1998  1  20  12  -22.5  35.3
1998  1  20  15    
1998  1  20  18  -23  36.1
1998  1  20  21    
1998  1  21  0  -23.4  36.5
1998  1  21  3    
1998  1  21  6  -23.9  37.2
1998  1  21  9    
1998  1  21  12  -24.6  38.5
1998  1  21  15    
1998  1  21  18  -25.2  39.9
1998  1  21  21    
1998  1  22  0  -25.4  41.4
1998  1  22  3    
1998  1  22  6  -25.6  42.9
1998  1  22  9    
1998  1  22  12  -25.8  44.3
1998  1  22  15    
1998  1  22  18  -25.8  45
1998  1  22  21    
1998  1  23  0  -25.7  45.5
1998  1  23  3    
1998  1  23  6  -25.6  46.3

Answer 1

[Star Strider]

Use the interp1 function:

[d, s, r] = xlsread('Lat_Long_Linear_Interpolation.xls');

dn = datenum([d(:,1:4) repmat([0 0],size(d,1),1)]);     % Convert Dates To Serial
nonan = ~isnan(d(:,5));                                 % Use Valid Data For Interpolation
latlon = interp1(dn(nonan),d(nonan,5:6), dn);           % Interpolate (Linear)
d_intrp = [d(:,1:4) latlon];                            % Reconstruct Full Data Matrix

[Damith]

Thanks so much. I appreciate your quick response.

[Star Strider]

My pleasure!