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

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

[dpb]

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]

Thank you dpb. Yes I've edited the code as per your suggestion.

[Ashish Uthama]

Did you try using NCREAD itself? (NCINFO will give you dimension info about a variable).

[alagu mathi]

Yes,I tried ncinfo() but still i could n't clear that problem.

[Mohnish sinha]

will you please write the revised code for extracting nc files, I am looking for the data for India...

Answer 1

[Ashish Uthama]

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]);

[alagu mathi]

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]

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]

What does these elements (1 1 1 etc.. ) represents in this [1 1 1],[360 181 1]?