Geocoding uses a postal address to identify the GPS lat/long coordinates at that location. International geocoding is when you match a mailing address to the GPS lat/long coordinates of a location anywhere in the world.
Too easy? Well that's one of the charms of international geocoding: it's a really simple idea. But it's sometimes really hard to execute.
See, geocoding accuracy is largely dependent upon the stability and modernization of the country in which a place is. First-world countries enjoy geocodes that are often accurate enough to get you right to the doorstep. Other countries aren't always so lucky. A good rule of thumb: the less reliable the postal system is, the less accurate the geocodes are going to be.
First let's talk about what geocodes are. The simplest explanation is that geocodes are GPS latitude/longitude coordinates that are tied to a postal mailing address. So if the address in question can accurately tell the postage where to go, the corresponding geocodes will successfully tell the GPS in your car where to go.
Geocodes come mostly in two flavors: interpolated and "rooftop level" accurate. "Rooftop level" geocodes are acquired by someone taking a device and walking right up to the premises in question, then recording the coordinates. Interpolated geocodes are acquired by taking two geocodes already on file and dividing the space between them evenly. The space is then applied to the addresses in between to estimate the geocode.
"Rooftop level" geocodes take more legwork and time to acquire, and are thereby more expensive, a cost that's usually passed on to you when you ask for the geocodes. Interpolated geocodes can be produced at the time of request, and don't take a physical presence at the location, so they're cheaper.
The speed in which these are returned also depend on your geocode provider. If they do the interpolation calculations when you ask for the geocodes, it may take longer to get your answer. If the geocode provider already has a vast database of previously interpolated geocodes, your response rate can be really fast.
So in short:
As stated above, both geocoding and validating the address the geocode is tied to are much more complicated when you take things outside places like the US and Western Europe. The less established a country's postal system is, the less accurate the geocodes are bound to be, because the geocodes are tied to the addresses. Unreliable addresses lead to unreliable geocodes.
The good news is the bulk of international communications (and similarly the need for geocodes) happens in more developed nations. So as long as you find a real stand-up provider you're in business.
The best way to ensure that you're getting a reliable international geocode is to make sure the address it's attached to is a real address. That's done with address validation. Using an address validation service to compare your address against a database ensures that it's real. Even in countries with less reliable records, the "valid" result from an address validation service gives you an extra level of reassurance. And if they took the time to mark the address down on the record, it's more likely they did the same with the geocode.
Moreover, it makes sure that the geocode you pick up doesn't lead you to somewhere that doesn't exist—ike an inactive address, or a huge rice field.
In the end, international geocodes are just like the ones you have back home. It's the same method, with the same kinds of results. Be sure you pick a solid international data provider that can help you get what you want, with the high levels of accuracy that you're looking for. Call us and we can help you get started; either we'll find a way to fill your needs, or we'll help you find someone else who can. In any case, we'll help you be the globetrotter you want to be.