Chapter 8. PostGIS TIGER geocoder


This chapter covers

  • Address normalization
  • Geocoding
  • 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. 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 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.

PostGIS TIGER geocoder requirements

To use the PostGIS TIGER geocoder, you must have PostGIS 2.0 or higher. If this doesn’t describe you, stop reading, upgrade, and then rejoin our discussion.

We’ll lead you through the following steps in this chapter so that you’ll have a fully functioning geocoder at the end:

1.  Installing the PostGIS TIGER geocoder

2.  Downloading the data from the U.S. Census Bureau for your region of interest

3.  Using an address normalizer to prepare your address

4.  Geocoding and interpreting the results

5.  Reverse geocoding

8.1. Installing the PostGIS TIGER geocoder

8.2. Loading TIGER data

8.3. Normalizing addresses

8.4. Geocoding

8.5. Reverse geocoding

8.6. Summary