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Creating hourly average data with geographic coordinates to produce 3D matrix

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Aristo Pacino
Aristo Pacino on 24 Jul 2021
Commented: dpb on 26 Jul 2021
I have 4 column matrix, which include irregular time, temperature, latitude and longitude. I want to creat 3-D matrix such that I have hourly averages of temperature within particular latitude and longitude grid. Thereby producing a 3D matrix of latitude x longitude x hourly averaged temperature.
Please find the attached dataset.
Thanks in advance!
  3 Comments
Aristo Pacino
Aristo Pacino on 25 Jul 2021
Hi @KSSV, please find the attached data file with this reply. They are using hourly decimal units.
Hello @dpb, they are sometimes missing hours and can be considered as NaN. I have attached the data files with this reply .
Thanks for your interest in the my question.

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Accepted Answer

dpb
dpb on 25 Jul 2021
Edited: dpb on 25 Jul 2021
rowfun to the rescue yet again... :)
tData=readtable();
longrid=-180:10:180;
latgrid=-90:10:90;
[~,~,~,tData.lon_g,tData.lat_g]=histcounts2(tData.lon,tData.lat,longrid,latgrid);
tGroup=rowfun(@mean,tData,'InputVariables','temp', ...
'GroupingVariables',{'hour','lon_g','lat_g'}, ...
'OutputVariableNames','temp');
produces:
>> [head(tGroup,5);tail(tGroup,5)]
ans =
10×5 table
hour lon_g lat_g GroupCount temp
____ _____ _____ __________ ______
0 2 14 1 89.94
0 3 5 1 99.68
0 3 7 1 87.31
0 3 9 1 100.86
0 3 15 1 71.35
23 35 14 2 89.96
23 35 15 1 101.81
23 35 16 1 107.89
23 35 18 1 101.6
23 36 9 1 91.3
>>
  6 Comments
dpb
dpb on 26 Jul 2021
Well, that's not the Answer of the link... <VBG>
Then see
doc xcorr2
It's in Signal Processing TB

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More Answers (1)

KSSV
KSSV on 25 Jul 2021
T = readtable('New Text document.txt') ;
t = T.hour ;
lon = T.lon ;
lat = T.lat ;
temp = T.temp ;
[c,ia,ib] = unique(t) ;
n = length(c) ;
iwant = cell(n,1) ;
for i = 1:n
iwant{i} = [t(ib==i) lon(ib==i) lat(ib==i) temp(ib==i)] ;
end
  1 Comment
Aristo Pacino
Aristo Pacino on 25 Jul 2021
Hi @KSSV, thank you very much but this is not what I desired. Sorry, I might be unclear but I wanted something for e.g within the longitude [-180 -170] and latitude [0 10] grid, I wanted the temperature to be sampled every one hour. So that I have some what like n x m x z matrix, where n is longitudinal size with grid size of 10 degrees, m is latitudinal size with grid size every 10 degrees and z is temperature size at every one hour sampling frequency.
I would be very happy if you could help me further but much thanks for your effort.
Cheers

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