[scoping] How to map NetCDF variables to folder directory and files

[dvalters]

Links in with #2 : here's an example of how we could map a netcdf file containing a pressure variable:

[dvalters@helmsdale sampledirmnt]$ tree --dirsfirst
.
├── pressure
│   ├── t1
│   │   ├── t1_p.png
│   │   └── t1_p.txt
│   ├── t2
│   │   ├── t2_p.png
│   │   └── t2_p.txt
│   ├── t3
│   ├── t4
│   ├── t5
│   └── variable_attrs.txt
├── dimension_metadata.txt
└── global_attrs.txt

[dvalters]

This is covered in more detail in the scoping document.