• A one-dimensional variable with the same name as a dimension and that specifies coordinate values for that dimension is a coordinate variable, for example the variables lat, lon, pres, and time in this example from the CF conventions: coordinate variables example

  xwind(n,k,j,i) is associated with the coordinate values lon(i), lat(j), pres(k), and time(n).

• A two-dimensional variable of type char is a string-valued coordinate variable if it has the same name as its first dimension, for example: string-valued coordinate variable example
• Multidimensional auxiliary coordinate variables, identified by a coordinates attribute, may be needed for projections, as in this example from the CF conventions: auxiliary coordinate variables example

• Make coordinate variables for every dimension possible (except for string length dimensions).
• Give each coordinate variable at least unit and long_name attributes to document its meaning.
• Use an existing netCDF Convention, preferably CF if applicable, for identifying your coordinate variables.
• Use shared dimensions to indicate that two variables use the same coordinates along that dimension. If two variable's dimensions are not related, create separate dimensions for them, even if they happen to have the same length.
• For search and discovery metadata, add global attributes that specify bounding boxes, time ranges, and keywords, for example as recommended in NetCDF Attribute Convention for Dataset Discovery.

2010 Unidata NetCDF Workshop > Best Practices