How Create Data Files?

[Camilo]

I've read the documentation about Creating Data Files[1] and try to
compile the examples in
gfortran but still can't figure out how to create the data files.

How should I format the data? i.e. how much spacing (if any) is there
between each column?

A sample data file that grads can read and its explanation would be a huge help.

Thanks for any help in advance.

[1] http://www.iges.org/grads/gadoc/aboutgriddeddata.html