Why postal code boundaries and administrative boundaries differ
A postal code area and a city or county boundary are drawn for entirely different purposes, and they frequently do not line up, which trips up anyone who assumes they should.
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#address-data
How country-code top-level domains relate to location data
A .de domain suggests a connection to Germany, but it is a weak and sometimes misleading signal compared to an actual IP-based or address-based location.
Why some countries publish better postal code data than others
Postal code data quality is not random, it tracks closely with how each country's postal authority builds, maintains, and shares its own reference data.
How disputed territories are handled in location data
Some coordinates sit in places where more than one government claims sovereignty. Location data has to describe reality on the ground without taking a political side.
ISO 3166-1 and 3166-2 codes, and where they get confusing
Country codes and subdivision codes look simple until you hit the exceptions. Here is what ISO 3166-1 and 3166-2 actually cover, and where confusion creeps in.
Postal code granularity: the UK versus the US versus everywhere else
A UK postcode can identify a single street or even a handful of buildings. A US ZIP code covers a much larger area. Postal granularity varies enormously by country.