Area code file Granularity

'fake' ISO language (not actually language codes) used to indicate area code file resolution or granularity. One or two digit aree codes are low resolution. Four or five high.
The two letter acronyms aren't to be taken literally. It's just a rough indication.

SizeAcronym
Federal Statefs
Province or Countypv
Regionrg
Municipalitymp
City, Town or Villagect
Neighbourhoodnh

For region files, all of these have a higher resolution then the default (no resolution two-letter code).
For area files the default is between 'Region' and 'Municipality'.
Currently used are 'rg' for low resolution and 'ct' for high resolution.
Note: This may change when required!