how to solve if interpolated data also contains NaN values

Question

Ismita 2024-3-13

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2093781-how-to-solve-if-interpolated-data-also-contains-nan-values

评论： Ismita 2024-3-13

I was trying to interpolate 'lat' and 'long' columns but even after interpolation first 4 data are still showing as NaN. For other data, interpolation is ok. I request for help /suggestion for the first 4 data. Thanks!

% Initialize lat_clean and long_clean with NaN values
lat_clean = NaN(size(lat));
long_clean = NaN(size(long));
% Update lat_clean and long_clean if the corresponding values in lat and long are not 9999.9
for i = 1:length(lat)
    if (lat(i) ~= 9999.9) && (long(i) ~= 9999.9)
        lat_clean(i) = lat(i);
        long_clean(i) = long(i);
    end
end
% Linear interpolation of NaN data
t_lat = 1:numel(lat_clean);
nan_lat = isnan(lat_clean);
lat_clean(nan_lat) = interp1(t_lat(~nan_lat), lat_clean(~nan_lat), t_lat(nan_lat));
t_long = 1:numel(long_clean);
nan_long = isnan(long_clean);
long_clean(nan_long) = interp1(t_long(~nan_long), long_clean(~nan_long), t_long(nan_long));
% Concatenate data to form new matrix
new_data = [time_numeric, density_dir, speed_dir, temperature_dir, distance_AU, lat_clean, long_clean];
% Write the new data to a text file
NHVOY2_Data = 'NH_VOY2_Data.txt';  % Replace with the desired output file path
dlmwrite(NHVOY2_Data, new_data, 'delimiter', '\t', 'precision', '%.6f');

result showing as

lat_clean =
       NaN
       NaN
       NaN
       NaN
   -1.4000
   -1.2000
   -0.9000
   -1.0000
   -0.3000

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Ismita 2024-3-13

移动：Sam Chak 2024-3-13

V2_small.txt

Thank you. In the attached file of the data, last column is for long and second last column is for lat.

Ismita 2024-3-13

thank you so much :)

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Answer 1

Chunru 2024-3-13

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2093781-how-to-solve-if-interpolated-data-also-contains-nan-values#answer_1424496

在 MATLAB Online 中打开

a = readmatrix("https://www.mathworks.com/matlabcentral/answers/uploaded_files/1641181/V2_small.txt");
a(a>9999.8) = nan
a = 24x6
0e+03 *

9920    0.1230         0    0.0372       NaN       NaN
9920    0.1230    0.0010    0.0372       NaN       NaN
9920    0.1230    0.0020    0.0372       NaN       NaN
9920    0.1230    0.0030    0.0372       NaN       NaN
9920    0.1230    0.0040    0.0372   -0.0014    0.0006
9920    0.1230    0.0050    0.0372   -0.0012    0.0008
9920    0.1230    0.0060    0.0372   -0.0009    0.0008
9920    0.1230    0.0070    0.0372   -0.0010    0.0007
9920    0.1230    0.0080    0.0372   -0.0003   -0.0002
9920    0.1230    0.0090    0.0372   -0.0005   -0.0002
b = fillmissing(a, 'linear')
b = 24x6
0e+03 *

9920    0.1230         0    0.0372   -0.0022   -0.0002
9920    0.1230    0.0010    0.0372   -0.0020   -0.0000
9920    0.1230    0.0020    0.0372   -0.0018    0.0002
9920    0.1230    0.0030    0.0372   -0.0016    0.0004
9920    0.1230    0.0040    0.0372   -0.0014    0.0006
9920    0.1230    0.0050    0.0372   -0.0012    0.0008
9920    0.1230    0.0060    0.0372   -0.0009    0.0008
9920    0.1230    0.0070    0.0372   -0.0010    0.0007
9920    0.1230    0.0080    0.0372   -0.0003   -0.0002
9920    0.1230    0.0090    0.0372   -0.0005   -0.0002