Open bands from several MODIS scenes with a loop

Question

YEMY 2018-10-30

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/427015-open-bands-from-several-modis-scenes-with-a-loop

评论： YEMY 2018-11-2

   Hello, I would like to know if there is any alternative way to open all these bands in a single loop ?
 Red{1} = hdfread('MOD09GA.A2004020.h17v05.006.2015085050751.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
          NIR{1} = hdfread('MOD09GA.A2004020.h17v05.006.2015085050751.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
          Red{2} = hdfread('MOD09GA.A2004047.h17v05.006.2015086041209.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
          NIR{2} = hdfread('MOD09GA.A2004047.h17v05.006.2015086041209.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
          Red{3} = hdfread('MOD09GA.A2004080.h17v05.006.2015087072318.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
          NIR{3} = hdfread('MOD09GA.A2004080.h17v05.006.2015087072318.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
          Red{4} = hdfread('MOD09GA.A2004114.h17v05.006.2015088010956.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
          NIR{4} = hdfread('MOD09GA.A2004114.h17v05.006.2015088010956.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
          Red{5} = hdfread('MOD09GA.A2004140.h17v05.006.2015089030618.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
          NIR{5} = hdfread('MOD09GA.A2004140.h17v05.006.2015089030618.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
          Red{6} = hdfread('MOD09GA.A2004177.h17v05.006.2015090215040.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
          NIR{6} = hdfread('MOD09GA.A2004177.h17v05.006.2015090215040.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
          Red{7} = hdfread('MOD09GA.A2004209.h17v05.006.2015092061947.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
          NIR{7} = hdfread('MOD09GA.A2004209.h17v05.006.2015092061947.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
          Red{8} = hdfread('MOD09GA.A2004243.h17v05.006.2015093025827.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
          NIR{8} = hdfread('MOD09GA.A2004243.h17v05.006.2015093025827.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
          Red{9} = hdfread('MOD09GA.A2004272.h17v05.006.2015094101457.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
          NIR{9} = hdfread('MOD09GA.A2004272.h17v05.006.2015094101457.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
          Red{10} = hdfread('MOD09GA.A2004290.h17v05.006.2015095025852.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
          NIR{10} = hdfread('MOD09GA.A2004290.h17v05.006.2015095025852.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
          Red{11} = hdfread('MOD09GA.A2004321.h17v05.006.2015096045825.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
          NIR{11} = hdfread('MOD09GA.A2004321.h17v05.006.2015096045825.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
          Red{12} = hdfread('MOD09GA.A2004353.h17v05.006.2015097022651.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
          NIR{12} = hdfread('MOD09GA.A2004353.h17v05.006.2015097022651.hdf', 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');

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Answer 1

Kojiro Saito 2018-11-1

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/427015-open-bands-from-several-modis-scenes-with-a-loop#answer_344582

在 MATLAB Online 中打开

I have two ideas.

1. Use for-loop

dataDir = '*.hdf';
listing = dir(dataDir);
for ii=1:size(listing, 1)
  fname = listing(ii).name;
  Red{ii} = hdfread(fname, 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
  NIR{ii} = hdfread(fname, 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
end

2. Use datastore

dataDir = '*.hdf';
readFcn = @(filename) readModis(filename);
fds = fileDatastore(dataDir, 'ReadFcn', readFcn);
ii = 1;
while hasdata(fds)
  s = read(fds);
  Red{ii} = s.red;
  NIR{ii} = s.nir;
  ii = ii+1;
end
function data = readModis(fpath)
  data.red = hdfread(fpath, 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b01_1');
  data.nir = hdfread(fpath, 'MODIS_Grid_500m_2D', 'Fields', 'sur_refl_b02_1');
end