# how can i combine 3 dimensional data and use pca function?

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성낙 홍 il 27 Giu 2023
Commentato: 성낙 홍 il 27 Giu 2023
HI, I want to combine two pressure data which have longitude 160 ~ 180 & -180 ~ -150.( latitude is same.)
I wanted to use pca function with this data, and plot with m_map.
% pressure
prs1prs1 = ncread('prs1.nc','sp');
prs2 = ncread('prs2.nc','sp');
prs2(1,:,:)=[];
prs=cat(1,prs1,prs2);
[a,b,c] = size(prs);
X = reshape(prs,a*b,c)';
X = X-ones(c,a*b).*repmat(mean(X,1),c,1);
X(isnan(X))=0;
% pca
[coeff,score,latent,tsquared,explained] = pca(X);
recoeff = reshape(coeff,[201,121,351]);
% time
day1 = datetime(1979,01,01);
day2 = datetime(2022,12,31);
time = day1:calmonths(1):day2;
time=datenum(time);
%lon
prs1lon = ncread('prs1.nc','longitude');
prs1lon = double(prs1lon);
prs2lon = ncread('prs2.nc','longitude');
prs2lon = double(prs2lon);
prs2lon(1,:)=[];
prslon=[prs1lon;prs2lon];
%lat
prslat = ncread('prs1.nc','latitude');
prslat = double(prslat);
% m_map
m_proj('lambert','lon',[160 210],'lat',[50 80])
m_pcolor(prslon,prslat,recoeff(:,:,1)');
colormap(jet);
shading flat
hold on
h=m_coast('patch','w')
m_grid('box','on','out');
hold on
I tried like this, but the figure does not show whole range.
How can I solve this??
Thank you.
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### Risposte (1)

Mrinal Anand il 27 Giu 2023
You can try changing the range of longitudes in the m_proj function to include a longer range of longitudinal values:
m_proj('lambert', 'lon', [160 -150], 'lat', [50 80])
You can probably adjust the longitudinal range to get the desired figure that you want.
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성낙 홍 il 27 Giu 2023
Thanks for your answer, your answer helped me to solve the problem.
Range of longitudes in m_proj was not problem,
but the prslon didn't matched with the m_proj range.
So I changed the prslon range.
Thanks again.

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