MATLAB: How to convert grid file to text file

asciigridMATLAB

Hi there.

Can you help me on how to convert this type of grid file into text file (lat, lon, amp, phase) for each column.

The grid file is attached

Best Answer

fid = fopen('Example.txt');
data = cell2mat(textscan(fid, '', 'HeaderLines', 5));
fclose(fid);
amps = data(1:2:end,:);
phases = data(2:2:end,:);
[nr, nc] = size(amps);
longs = linspace(0, 360, nc+1);
longs(end) = [];
lats = linspace(-90, 90, nr+1);
lats(end) = [];
subplot(2,1,1);
surf(longs, lats, amps);
xlabel('long')
ylabel('lat')
title('amplitudes')
subplot(2,1,2)
surf(longs, lats, phases)
xlabel('long')
ylabel('lat')
title('phases')

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MATLAB: How to read, change and write data back into the same txt file, at the same place

To replace a specific bit of text in a text file, you're going to have to rewrite the entire file. Assuming the files above are representative of your real files, this shouldn't be too time-consuming, because the files are small and easily fit in memory. So I recommend just reading in the entire file at once rather than looping over lines. Using either startsWith (in newer versions of Matlab) or strncmp (in older ones) will be a bit more efficient than your method of comparing individual characters.

The other key to replacing the text with your newly-calculated number is to make sure the new value has the same number of characters as the old one; you can make sure of that by using sprintf instead of num2str when converting your new value into a string.

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txt = fileread(file);
% Split into lines
txt = regexp(txt, '\r\n', 'split');
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           startsWith(txt, 'R') | ...
           startsWith(txt, 'TS') | ...
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MATLAB: How to store data extracted from multiple NetCDF into already extracted txt file and add next year data after last line of previous iteration in the same txt file.

% new code to extract data from netcdf file to SWAT format text file.

data =[];

Files = dir('*.nc');

for k=1:length(Files)

FilesNames = Files(k).name;

for t=1:2

pr = ncread(FilesNames,'rainfall_amount');

long = ncread(FilesNames,'x');

lat = ncread(FilesNames,'y');

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for j = 716:746(lat);

for i = 328:368(long);

outfile =sprintf('%d_%d_PCP.txt',lat(j),long(i));

fopen all;

v = pr(i,j,:);

data2 = (v);

data2(isnan(data2)) = -99.0;

% outfile =sprintf('%d_%d_PCP.txt',lat(j),long(i));

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fid = fopen(outfile,'At');

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end

fclose all;

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disp([outfile 'created'])

% original code source:

% http://dficklin.weebly.com/netcdf-to-swat-climate-input-files.html

Best Answer

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MATLAB: How to read, change and write data back into the same txt file, at the same place

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