ncwrite - Write data to NetCDF file

Syntax

Description

ncwrite(filename,varname,vardata) writes the numerical or char data in vardata to an existing variable varname in the NetCDF file filename. ncwrite writes the data in vardata starting at the beginning of the variable and extends unlimited dimensions automatically, if needed.

If the NetCDF file or the variable do not exist, use nccreate to create them first.

ncwrite(filename,varname,vardata,start,stride) writes vardata to an existing variable varname in file filename beginning at the location given by start. stride is an optional argument that specifies the inter-element spacing of the data written. Use this syntax to append data to an existing variable or write partial data.

Tips

• If the variable varname already exists, ncwrite expects the datatype of vardata to match the NetCDF variable data type.

• If the variable varname has a _FillValue, scale_factor or add_offset attribute, ncwrite expects data in double format and casts vardata to the NetCDF data type, after applying the following attribute conventions in sequence:

  1. Subtract the value of' theadd_offset attribute from vardata.

  2. Divide vardata by the value of the scale_factor attribute.

  3. Replace NaNs in vardata by the value of the _FillValue attribute. If this attribute does not exist, ncwrite tries to use the fill value for this variable as reported by the NetCDF library.

Input Arguments

Examples

Create a new netcdf4_classic file, and write a scalar variable with no dimensions. Add the creation time as a global attribute.

nccreate('myfile.nc','pi');
ncwrite('myfile.nc','pi',3.1);
ncwriteatt('myfile.nc','/','creation_time',datestr(now));
% overwrite existing data
ncwrite('myfile.nc','pi',3.1416);
ncdisp('myfile.nc');

Create a netcdf4_classic file with a variable defined on an unlimited dimension. Write data incrementally to the variable.

nccreate('myncfile.nc','vmark',...
         'Dimensions', {'time', inf, 'cols', 6},...
         'ChunkSize',  [3 3],...
         'DeflateLevel', 2);
ncwrite('myncfile.nc','vmark', eye(3),[1 1]);
varData = ncread('myncfile.nc','vmark');
disp(varData);
ncwrite('myncfile.nc','vmark',fliplr(eye(3)),[1 4]);
varData = ncread('myncfile.nc','vmark');
disp(varData);   

See Also

nccreate | ncdisp | ncinfo | ncread | ncwriteatt | netcdf

Tutorials

• Exporting to Network Common Data Form (NetCDF) Files