High-level interface

Getting information

NetCDF.ncinfoFunction
ncinfo(filename)

prints information on the variables, dimension and attributes conatained in the file

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Reading data

NetCDF.ncreadFunction
ncread(filename, varname)

reads the values of the variable varname from file filename and returns the values in an array.

Keyword arguments

  • start Vector of length ndim(v) setting the starting index for each dimension
  • count Vector of length ndim(v) setting the count of values to be read along each dimension. The value -1 is treated as a special case to read all values along the dimension

Example

To read the second slice of a 3D NetCDF variable, you can write:

ncread("filename","varname", start=[1,1,2], count = [-1,-1,1])
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NetCDF.ncread!Function
ncread!(filename, varname, d)

reads the values of the variable varname from file filename and writes the results to the pre-allocated array d

Keyword arguments

  • start Vector of length ndim(v) setting the starting index for each dimension
  • count Vector of length ndim(v) setting the count of values to be read along each dimension. The value -1 is treated as a special case to read all values from this dimension

Example

To read the second slice of a 3D NetCDF variable one can write:

d = zeros(10,10,1)
ncread!("filename","varname", d, start=[1,1,2], count = [-1,-1,1])
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Writing data

NetCDF.ncwriteFunction
ncwrite(x::Array,fil::AbstractString,vname::AbstractString)

Writes the array x to the file fil and variable vname.

Keyword arguments

  • start Vector of length ndim(v) setting the starting index for writing for each dimension
  • count Vector of length ndim(v) setting the count of values to be written along each dimension. The value -1 is treated as a special case to write all values along the dimension. This is usually inferred by the given array size.
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Reading attributes

NetCDF.ncgetattFunction
ncgetatt(filename, varname, attname)

This reads a NetCDF attribute attname from the specified file and variable. To read global attributes, set varname to Global.

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Writing attributes

NetCDF.ncputattFunction
ncputatt(nc::String,varname::String,atts::Dict)

Writes the attributes defined in atts to the variable varname for the given NetCDF file name nc. Existing attributes are overwritten. If varname is not a valid variable name, a global attribute will be written.

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Creating files

NetCDF.nccreateFunction
nccreate (filename, varname, dimensions ...)

Creates a variable in an existing NetCDF file or generates a new file. filename and varname are strings. After that follows a list of dimensions. Each dimension entry starts with a dimension name (a String), and may be followed by a dimension length, an array with dimension values or a Dict containing dimension attributes. Then the next dimension is entered and so on. Have a look at examples/high.jl for an example use.

Keyword arguments

  • atts Dict of attribute names and values to be assigned to the variable created
  • gatts Dict of attribute names and values to be written as global attributes
  • compress Integer [0..9] setting the compression level of the file, only valid if mode=NC_NETCDF4
  • t variable type, currently supported types are: const NC_BYTE, NC_CHAR, NC_SHORT, NC_INT, NC_FLOAT, NC_LONG, NC_DOUBLE
  • mode file creation mode, only valid when new file is created, choose one of: NC_NETCDF4, NC_CLASSIC_MODEL, NC_64BIT_OFFSET
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