• 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
• 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 listed in 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 of standard_name and axis attributes is recommended.
• 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.

2012 Unidata NetCDF Workshop > Best Practices for Data providers