How should I format an address for geocoding?

Addresses are a method of describing a physical locations in our world.  Geocoding assigns geographic coordinates to addresses so that they can be placed as points on a map.  However, geocoding accuracy will largely depend on how well your addresses are formatted, and how complete they are.  When geocoding, the address is interpreted by identifying address attributes contained in the address and comparing those attributes against reference data.  These attributes help pinpoint an address to a specific geographic coordinate.  To make geocoding as efficient as possible, it is recommended that you store your addresses in multiple fields (i.e. columns): primary address, secondary address, post office box, city name, state and zip code, see table below.

Field or Column Attributes Example
Primary Address number, predirectional (if applicable.  i.e., N, S, E, W, NE, NW, SE, SW), street name, street suffix (i.e. street, avenue, etc.) and postdirectional (if applicable) 1007 E GRAND AVE
Secondary Address unit designator (i.e. APT - apartment, BLG - building, FL - floor, STE - suite, UNIT, RM - room, DEPT - department, etc.), unit number RM G14
Post Office Box post office box designator (i.e. PO Box), post office box number  
City Name city DES MOINES
State state IA
Zip Code ZIP, ZIP+4 50319

Common Issues

  1. Inconsistent abbreviations of street suffixes (e.g. Avenue may commonly be abbreviated AV, AVEN, or AVN or fully spelled out as avenue).  Best practice is to use standard abbreviations approved by USPS [1].
  2. Abbreviating directionals (i.e., N, S, E, W, NE, NW, SE, SW) when part of street name.  When a directional is part of the primary street name, it should be spelled out (e.g. NORTH ST).
  3. Inconsistent format for county, state and local highways.  Generally, when highways are part of the primary street name, they should be spelled out (e.g. COUNTY HIGHWAY 33, COUNTY ROAD 5, STATE HIGHWAY 141, US HIGHWAY 169) [2].
  4. Misspelled city and street names.
  5. Incomplete address - need to have primary address, city name, state and zip code.  Geocoding is possible with only a partial address (e.g. city name and state, and zip code), but it is not as precise.
  6. Address is new and not recognized in reference data.

[1] Postal Addressing Standards, Standard Street Suffix Abbreviations

[2] Postal Addressing Standards, County, State, Local Highways

Program Area
Open Data, Geocoding, Address, Quality

Printed from the Iowa Department of Management website on April 21, 2018 at 6:24am.