PCA Graph of Data Comes Up Blank

2 views (last 30 days)
Mike Zimmers
Mike Zimmers on 2 May 2021
Commented: Mike Zimmers on 2 May 2021
I am running an example code from the Climate Data Toolbox and I am having issues plotting the graph of the principle component of my data. When I run the code, it is resulting in a blank graph. The data is the file attached. The following is my code.
clc
close all
clear all
%% TS
filename = 'data';
S = dir(fullfile(filename,'*.txt'));
for k = 1:numel(S)
fnm = fullfile(filename,S(k).name);
mtx1 = load(fnm);
mtx1 = normalize(mtx1);
mtx = reshape(mtx1,72,144);
TS{k} = mtx;
TS{k}(TS{k} == -1000) = NaN;
end
TS_cat = cat(3,TS{:});
lat = (-90:2.5:90);
lon = (-180:2.5:180);
[Lon,Lat] = meshgrid(lon,lat);
figure
TS_cat = fillmissing(TS_cat,'linear');
imagescn(lon,lat,mean(TS_cat,3))
axis xy
cmocean thermal
xlabel 'longitude'
ylabel 'latitude'
%%
[eof_maps,pc,expv] = eof(TS_cat);
% Plot the first mode:
figure
imagesc(lon,lat,eof_maps(:,:,1))
axis xy image
cmocean('curl','pivot')
title 'The first EOF mode!'
t = length(pc(1,:));
%
figure
% subsubplot(3,1,1)
plot(t,pc(1,:))
box off
axis tight
ylabel 'pc1'
title 'The first principal components'
How would I fix this?
Thanks in advance.

Answers (1)

Chad Greene
Chad Greene on 2 May 2021
I think you're mixing and matching different ways of defining filenames. As a result, dir is unable to find the files you're looking for.
When I ran your code, this came up empty:
S = dir(fullfile(filename,'*.txt'));
The easiest solution is to navigate directly to the folder where all of your .txt files are, and do
S = dir('*.txt');
I was able to get around all of this by manually writing the filename in this line:
mtx1 = load('data.txt');
But that of course only loads the single example file you uploaded. As a result, pc only contains one entry, becauese there's only one timestep.
  6 Comments
Mike Zimmers
Mike Zimmers on 2 May 2021
This is the image that I get when I run
imagesc(sum(isnan(TS_cat),3))
colorbar
I tried to see if changing
TS{k}(TS{k} == -1000) = NaN;
from NaN to 0 in the loop, makes any difference but it gives the same figure.
Mike Zimmers
Mike Zimmers on 2 May 2021
I changed
TS{k}(TS{k} == -1000) = NaN;
to
TA{k}(TA{k} <= 0) = NaN;
in the loop and this is the figure that is produced:

Sign in to comment.

Categories

Find more on Climate Science and Analysis in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!