Geocoding for Neighborhood Research February 2016

1. Geocoding for Neighborhood ResearchFebruary 2016

2. What is Geocoding? • Geocoding uses a description of a location, most typically a postal address or place name, to find geographic coordinates from spatial reference data such as building polygons, land parcels, street addresses, postal codes, etc.

3. What Happened? • Geocoding used to be easy! • ESRI switched from unlimited geocoding to pay-per-search geocoding • Bulk geocoding became expensive for many users • Special thanks to Eric Burnstein for testing and reporting on current geocoding options • Before: • Now:

4. What Options are Available? • We tested a number of geocoding services. The best option will depend on the specific needs of the research project. • U.S. Census Geocoder • Smarty Streets • ArcGIS Online • Semaphore ZP4 • Texas A&M Geoservices • SAS Proc Geocode • Google/Bing/Mapquest API • Local Geocoders (ie. Washington,DC MAR geocoder)

5. Which is Best for Me? • To assess the geocoding options, first answer the following questions… • How many addresses do I need to geocode? • What is the quality of my address data? • Are the addresses limited to one city? State? The entire U.S.? • Are the addresses mostly in Metro areas? Rural areas? • How precise do I need the final output? • How much project money is budgeted for geocoding? • What is the end-goal (appending Census data, mapping for the web, etc.)?

6. Choosing a Geocoder • Census Geocoder • Are the addressesall local? • Over or under 1,000 records? • No • Under • Over • Yes • Does the project have budget for Geocoding? • Local Geocoder • SAS Proc Geocode • No • Yes • Need to find unmatched addresses? • Desired accuracy of results • Standard • Texas A&M Geoservices • Yes • High • ArcGIS Online

8. ArcGIS Online • Best use: Project with sufficient budget that requires high level of accuracy. • Pros: • Most accurate option • Fast processing • Cons: • Expensive and difficult credit system • Higher learning curve than alternatives

9. U.S. Census Geocoder • Best use: Project with a small number of addresses and a tight budget. • Pros: • Completely free • Easy to use • Cons: • Limited to 1,000 addresses • Lower accuracy than alternatives

10. SAS Proc Geocode • Best use: Project with a large number of addresses and a tight budget. • Pros: • Free (inside UI) • Handles unlimited addresses • Cons: • Basic knowledge of SAS required • Lower accuracy than alternatives

11. Texas A&M Geoservices • Best use: Project with sufficient budget that requires high level of accuracy and limited time to set-up and learn ArcGIS online. • Pros: • Easy to use • Reasonable cost • Cons: • Slower than the alternatives • Not the cheapest or the most accurate

12. Local Geocoders • Best use: Project uses addresses for only one city. • Pros: • Highly accurate • Usually free to use • Cons: • Limited to a single city • Need to learn a new tool for each city

13. Google/Bing/Mapquest API • Best use: Project with good quality address data, no or low budget. • Pros: • Can use Stata. R, and other tools • Many are already be familiar withthese services • Cons: • Limited free queries per IP per day • Less transparent on quality of matches • Enterprise API key is expensive

14. Other Options (not generally recommended) Semaphore ZP4

15. Hybrid Geocoding Approaches • 50,000 addresses • 10,000 unsuccessful geocodes • 40,000 successful geocodes • 5,000 successful geocodes • 45,000 successful geocodes

16. Questions? Please ask now or email me! rpitingolo@urban.org

17. Thank You!