The TLD, or Top Level Domain is a two-letter standardized code that helps MetaLocator consistently identify the intended country of either a user's search term, or a location in your database regardless of language. This is used in geocoding, which is the process of translating free-form text into a latitude and longitude.
The accuracy of the geocoding results of both your location data and user searches is essential to getting quality results from MetaLocator.
An authoritative list can be found here. Also this tool can be useful.
The TLD or ISO, two-digit Country code is required for each location. Also each location must have the Country name that is consistent throughout the MetaLocator data. Meaning there can't be a TLD of US and Country name of USA, United States, etc.
There are two key areas the TLD is used within MetaLocator:
When geocoding your address data, also known as the Data TLD.
When geocoding the user's search term, also known as the Search TLD.
Data TLD: The TLD used when geocoding your address data should be provided in the TLD field for each location, or imported in the TLD column for each row. When left empty or set incorrectly, it can result in poor or incorrect geocoding results.
Search TLD: In an Interface that is searching a single country, the Search TLD can be controlled by the "Base TLD" setting found under Interface > Data Settings > Base TLD. This should be changed to the correct TLD. In an Interface that is searching multiple countries, a Country drop-down field should be displayed. Similarly, the setting found under Data Settings > "Choose the TLD from the selected country for bias?" should be set to "Yes". This allows the system to ignore the Base TLD setting, and instead pull the TLD from the user's selection from the country drop-down list.