Geocoding for Neighborhood Research February 2016

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.

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:

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)

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.)?

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

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

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

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

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

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

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 with these services Cons: Limited free queries per IP per day Less transparent on quality of matches Enterprise API key is expensive

Other Options (not generally recommended) Semaphore ZP4

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

Questions? Please ask now or me!

Thank You!