Append data to 3rd dimension in loop
11 次查看(过去 30 天)
显示 更早的评论
I have 68 4320x2160x24 files that I use a for loop to read in and perform some tasks on, then I iteratively store output in a new variable. Towards the end of the script, I want to iteratively store the 4320x2160x12 matrix ndvi_mmax into a 4320x2160x(12*68) matrix (NDVI_monthmax). My current attempts have failed, I'm notsure whther I need to create a 4D matrix or if I need another, nested, loop, or convert to a cell. Any help appreciated.
startyear = 1982;
endyear = 2015;
nyears = length(startyear:endyear);
nmonths = nyears*12;
%Preallocate variables for output file
NDVI_mean = zeros(4320,2160,nyears); % mean annual NDVI
NDVI_monthmax = zeros(4320,2160,nmonths); % highest monthly mean NDVI
MD = zeros(4320,2160,nyears); % # of missing datapoints each year
%load data and define variables
for i = 1:nyears
yr = (startyear-1)+i;
filename1 = sprintf('ndvi3g_geo_v1_%d_0106.nc4', yr);
filename2 = sprintf('ndvi3g_geo_v1_%d_0712.nc4', yr);
fullFileName1 = fullfile(myFolder, filename1);
fullFileName2 = fullfile(myFolder, filename2);
ncid1 = netcdf.open(fullFileName1);
ncid2 = netcdf.open(fullFileName2);
%disp(filename1)
%ncdisp(fullFilename1)
NDVI1 = ncread(fullFileName1, 'ndvi');
NDVI2 = ncread(fullFileName2, 'ndvi');
flag1 = ncread(fullFileName1, 'percentile');
flag2 = ncread(fullFileName2, 'percentile');
NDVI = cat(3,NDVI1,NDVI2);
NDVI = double(NDVI);
NDVI(NDVI == -32768) = NaN;
NDVI(NDVI == -5000) = NaN;
NDVI = NDVI/10000; % scaling factor
flag = cat(3,flag1,flag2);
NDVI(flag >= 4000) = NaN; %remove snow/cloud flagged pixels
latitude = ncread(fullFileName1, 'lat');
longitude = ncread(fullFileName1, 'lon');
md = sum(isnan(NDVI),3);
ndvi_mean = nanmean(NDVI,3);
ndvi_monthmax = max(reshape(NDVI,4320,2160,2,12),3); % max NDVI each month
ndvi_monthmax(:,:,2:end,:) = [];
ndvi_mmax = squeeze(ndvi_monthmax); % remove 3rd dimension
%HERE'S WHERE I RUN INTO PROBLEMS:
NDVI_monthmax(:,:,12) = ndvi_mmax;
%THIS WORKS FINE:
NDVI_mean(:,:,i) = ndvi_mean;
MD(:,:,i) = md;
end
0 个评论
采纳的回答
Kevin Holly
2022-9-28
Assuming you have 68 files that are distinguished based on the year and the above is only looking at 33 of the files/years.
3D - 4320x2160x(12*68)
NDVI_monthmax(:,:,(i-1)*12:(i-1)*12+12) = ndvi_mmax;
or 4D - 4320x2160x12x68
NDVI_monthmax(:,:,:,i) = ndvi_mmax;
2 个评论
Kevin Holly
2022-9-28
Or if you just want to append:
NDVI_monthmax = [NDVI_monthmax; ndvi_mmax];
Be sure to write the following command before your for loop:
NDVI_monthmax = [];
更多回答(0 个)
另请参阅
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!