Attributes, Dimensions, and Variables

The three basic components of a netCDF file are described below.


Attributes can contain auxiliary information about an entire netCDF file ( global attributes) or about a single netCDF variable. Every attribute has a name, data type, and length associated with it. It is common to repeat attribute names for each variable. For example, every variable in a netCDF file might have an attribute named "Units". Note however, that variables cannot have multiple attributes with the same names.


Dimensions are named integers that are used to specify the size (or dimensionality ) of one or more variables. Each dimension must have a unique name, but a variable and dimension can share a name. Each netCDF file is allowed to have one boundless (or unlimited ) dimension. Most often the unlimited dimension is used as a temporal variable, allowing data to be appended to an existing netCDF file. An example of this use is shown later.


Variables are multidimensional arrays of values of the same data type. Each variable has a size, type, and name associated with it. Variables can also have attributes that describe them.