The “What” and “Where” of any physical place

‍When both parts of a Plackey come together, the final result reads as What@Where. This is a unique way of shedding light on both the descriptive element of a place as well as its geospatial position in the physical world via a single identifier.

The first three characters refer to the Address Encoding, creating a unique identifier for a given address. An address at “555 Main Street Suite 105” will have a different Address Encoding than “555 Main Street Suite 106.” However, "444 Second Street, Suite 4" will have the same address encoding as "444 2nd St. #4" to adjust for common address formats.

The second set of three characters in the What Part refers to the POI Encoding. If a specific place has a location name (like "Central Park") and is already included in the Placekey reference datasets, these characters will be present. The benefit of the POI Encoding is that it can point to a specific point-of-interest that may have existed at a certain address at a given point in time.

The Where Part, on the other hand, is made up of three unique character sequences, built upon Uber’s open source H3 grid system. This information in the Where Part is based on the centroid of that place. In other words, we take the latitude and longitude of a specific place and then use a conversion function to determine a hexagon in the physical world, representing about 15,000 sq. meters, containing the centroid of that place. The Where Part of the Placekey is, therefore, the full encoding of that hexagon.