While Singapore is a city-state and does not have administrative
divisions like states or counties, many users expect some form of
subnational structure. Singapore is officially divided into five
Community Development Councils (CDCs), which could be considered
analogous to city districts.
In most larger cities, we model city-districts as administrative
divisions one level below the lowest national level. By analogy, it
could make sense to model CDCs as administrative units for Singapore.
This would provide a more consistent structure and make working with the
dataset more intuitive.
We have modeled them already as ADM1 in the past and later converted
them into regions. The '01' code is a remnant. We should either
reestablish the CDC as adm1 or purge the admincode1.
For GeoNames ID 1880252 (Feature class: Capital), can it be not attached to any region? Currently GeoNames ID 1880252 is attached to region "Singapore, SG.01", which is very misleading.
There are many entries in ROR that point to
ID 1880252, and their CDC is definitely not Central Singapore (SG.01). This ROR entry, for example,
https://ror.org/02e7b5302 , is located in SG.05, but their ROR record points to SG.01. This ROR record, is then used by ORCID, making the record looks quite weird and misleading.
I'm not sure if I make much sense, since I'm not familiar with GeoNames structure, but hopefully you can consider my suggestion.