The Short Answer
A geocode is the GPS coordinates (or the latitude and longitude) of a physical address. There are two main ways to get a location's geocode. One is to physically stand in the spot you want to geocode and use a GPS device to give you the precise latitude/longitude coordinates of where you're standing. The second geocoding method is to interpolate a location's geocoordinates by using math to approximate its position.
SmartyStreets provides geocodes as part of our address validation services.
Everything You Ever Needed to Know About Geocodes
A "geocode" is just a fancy, shorter way of saying “a latitudinal/longitudinal coordinate”—much in the same way that "geocaching" is just a fancy way of saying "scavenger hunt." In other words, a geocode is the GPS coordinates for a specific location.
So, if geocodes are GPS coordinates, then geocoding is converting a location's description from one format (like a street address) into that location's specific GPS coordinates. Geocoding can be done a number of different ways that differ in methods, costs, and results.
How Does One "Geocode"?
The most accurate, most specific way to geocode is really simple. It's also the hardest. The best way to get the geocode of a specific location is to personally travel to that location and mark it on a GPS device. The GPS device will then tell you the precise latitude and longitude of that exact location. Not a very practical approach if you have hundreds—or even millions—of locations to pinpoint, but still the most accurate way to geocode.
Try to imagine how long it would take you to geocode a whole city this way. (Hint: It would take a lot of time.) If you're interested in building a repository of geocodes through this method, we recommend packing a lunch. And a sleeping bag.
There's an alternative to this ultra-high-accuracy, high-cost method of geocoding. It's called "interpolation." You may have heard the term before, likely used by a math teacher. Interpolation isn't just useful in high school math classes, though. It's also used in other practices—like geocoding. This method adds considerable speed to the geocoding process, though it is slightly less accurate than physically geocoding an address. Despite the complexity of the math involved, the concept itself is surprisingly simple, and it works like this:
Take a random street. For simplicity's sake, we'll say a straight, residential street that terminates in intersections at both ends. Now let's suppose we have two geocodes that are in close proximity to the addresses on the street we want to know about. And let's assume those two geocodes are at either end of the street, that is, at either intersection. Once we have this information, we can use math to determine what's in the middle. When we use interpolation, we say, "Well, we start with point A, and we end with point D, so in between must be point B and point C."
Fortunately, this method of determining geocodes is a process that can be automated by way of computer programs.
When we use math to determine where point B and point C are between point A and point D, the math puts the geocodes at regular intervals and set patterns, which is not necessarily the way that homes and businesses are built. The fact is, people put buildings wherever they feel like. So the precise physical geocode of a home may be slightly different from the interpolated geocode for that same home. When we use interpolation to create geocodes, we're creating geocodes that are "street-level" accurate, but not "rooftop accurate."
Accuracy Depends on Your Needs
Unless you need laser-guided accuracy (like a GPS app might), you likely do not need to use the door-to-door geocoding method. The majority of people don't need geocodes that specific. That's why SmartyStreets gives you data produced via interpolation. Then we give you a whole lot more.
First, we take the address you've given us, we standardize it and complete it, and we check it for validity. This is important for two reasons. One, because we make sure the geocode you’re looking for is actually tied to a real location that currently receives mail. Second, because we complete the address by adding missing information such as the ZIP+4 postal code , we make sure that the address is as accurate as it can be before we match it against interpolated geocode data.
That data is built from the combination of the US Census Bureau's TIGER data and supplemental data we assimilated from additional organizations to improve the accuracy of our coordinates. And, because of our lightning-fast computer systems developed and maintained by our world-class tech gurus, when you give us the address we can immediately give you the geocode that matches that address. So we save you time and money, and we give you the most accurate street-level data possible.
What about Google?
Sometimes services like Google will tag locations that don't exist.
Places like Google and Bing usually do rooftop-level accuracy on their geocodes. That's so they can give you GPS directions to a location. It's helpful when you want to know how to drive to where you're going. What they don't do is check for the validity of an address, like we do. That means if conditions aren't perfect (you entered the address incorrectly, the area isn't well mapped, etc.), Google may actually be dropping the pin on the map when it should be telling you it couldn't find what you were looking for.
So if you're counting on a mapping service to provide you with geocodes, you may find yourself requesting geocodes to a place that's no longer an active mailing address, isn't one yet, or isn't a real address at all. As many have already experienced, this is a problem even if you're looking for physical addresses rather than geocodes.
Since SmartyStreets' first love is address validation, it's the first thing we check. And if the place doesn't exist, we won't give you the geocodes for it.
Why Did I Care about All of This Long Enough to Read to the End?
So at the end of the day, SmartyStreets' geocodes are accurate enough to meet your needs, they're less expensive, and they're a whole lot quicker than the competition. And best of all, by combining geocoding with address validation, you can be sure the data we give you is reliable.