How to extract the data from .nc file based on longitude and latitude,time?

2014 5 17
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更新时间：2021 6 2
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Hi, I have to extract the data from netcdf file based on lat,long and time. I have written the following code.
ncid = netcdf.open('\C:\Users\divecha21\Desktop\errorBar\tasmax_day_BNU-ESM_rcp85_r1i1p1_20060101-21001231.nc','NC_NOWRITE');
peaksData = ncinfo('\C:\Users\divecha21\Desktop\errorBar\tasmax_day_BNU-ESM_rcp85_r1i1p1_20060101-21001231.nc','tasmax');
ncdisp('\C:\Users\divecha21\Desktop\errorBar\tasmax_day_BNU-ESM_rcp85_r1i1p1_20060101-21001231.nc','tasmax');
[ndim, nvar, natt, unlim] = netcdf.inq(ncid)
[dimname, dimlength] = netcdf.inqDim(ncid, 0)
[dimname, dimlength] = netcdf.inqDim(ncid, 1)
[dimname, dimlength] = netcdf.inqDim(ncid, 2)
lon = netcdf.getVar(ncid,0,0,128)
%time = netcdf.getVar(ncid,2,0,34675)
lat = netcdf.getVar(ncid,1,0,64)
latlim = [5.25 36.75];
lonlim = [60.25 97.25];
precJanuary = netcdf.getVar(ncid,2,[60.25 5.25 1],[97.25 36.75 1]);
Actually I have global temperature data i have to extract only india. After execution,I got the following error.
>> sample1
Error using ncread Expected start to be integer-valued.
Error in internal.matlab.imagesci.nc/read (line 557) validateattributes(start,{'numeric'},...
Error in ncread (line 58) vardata = ncObj.read(varName, varargin{:});
Error in sample1 (line 27) precJanuary = ncread('\C:\Users\divecha21\Desktop\errorBar\tasmax_day_GFDL-ESM2M_rcp85_r1i1p1_20060101-20101231.nc','tasmax',[60.25 5.25 1],[97.25 36.75 1]);
Can any one help me to clear this? I am new to matlab.
Thank you

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dpb
dpb 2014-5-17
Format your code to be legible. Add two blanks in front of first line and reintroduce line breaks where they belong. Keep at it until looks right in preview window. Don't put extra blank lines in; if do need one, reinsert the leading double-blanks to get back to code formatting (yes, I know, it's a pita; but TMW in their infinite wisdom uses a textbox w/ default word-wrap 'on' for a code forum... :( )
alagu mathi
alagu mathi 2014-5-18
Thank you dpb. Yes I've edited the code as per your suggestion.
Ashish Uthama
Ashish Uthama 2014-5-19
Did you try using NCREAD itself? (NCINFO will give you dimension info about a variable).
alagu mathi
alagu mathi 2014-5-20
Yes,I tried ncinfo() but still i could n't clear that problem.
Mohnish sinha
Mohnish sinha 2014-11-10
will you please write the revised code for extracting nc files, I am looking for the data for India...

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 采纳的回答

Ashish Uthama
Ashish Uthama 2014-5-20
编辑：Ashish Uthama 2014-5-20

0 个投票

The nc* functions and the netcdf.* functions represent two independent ways to access a NetCDF file. I would recommend sticking to nc* functions until you get comfortable enough to directly access the NetCDF library interface using the netcdf.* functions (it uses C style indexing and dimension ordering which is different from what nc* functions report and use).
Instead of
precJanuary = netcdf.getVar(ncid,2,[0 0 0],[128 64 1]);
try
precJanuary = ncread(filename, varname,[1 1 1],[128 64 1]);

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alagu mathi
alagu mathi 2014-5-21
编辑：alagu mathi 2014-5-24
Thank you @Ashish Uthama.Yes i have edited the code as per your suggestion.I have south_india.fig(like shape file)i have to extract the data only that region.
Jonas Damsbo
Jonas Damsbo 2018-12-27
Hi Ashish Uthama
I try to use your code line:
z = ncread(ncfiles(i).name,'z',[1 1 1],[360 181 1]);
But I got the error:
Index exceeds array bounds. Why?
Lee Key
Lee Key 2021-6-2
编辑：Lee Key 2021-6-2
What does these elements (1 1 1 etc.. ) represents in this [1 1 1],[360 181 1]?

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