This chapter covers:
- Geocoding
- Address standardization
- Reverse geocoding
What is a geocoder? It’s a utility that takes a textual representation of a street address and finds its geographic position using data such as street centerline geometries. The textual representation of an address often goes thru a standardization process called "Address normalization" or "Address Standardization" that takes the textual representation and breaks it into its component parts such as street number, street name, suffix etc and ensures same type pieces are always represented the same. It is this standardized address that geocoders work with. Geocoders generally return the longitude and latitude.
In this chapter, we’re going to focus on the PostGIS geocoder specifically designed for TIGER. The TIGER acronym stands for Topologically Integrated Geographic Encoding and Referencing, and it’s a geospatial database maintained by the U.S. Census Bureau. The structure is topologically defined with edges, nodes, and faces very similar in structure to how postgis_topology extension structures data. The database encompasses key features of geographic interest in the entire United States, including political boundaries, lakes, reservations, major and minor roads, rivers, and so on.