GIS Cookbook: Recipe - How to Geocode Addresses  
Keywords: Geoprocessing, geocode, geocoding, address, address matching, street, zip, zone, address number, street name, location, address table
Category: Geocoding
Software: ArcView 3.2

Problem: I have a list of patients’ addresses. How do I plot their locations on a map?

Description: buffers and density estimation.

Scenario:
A fictitious epidemiological study taking place in Atlanta, Georgia, will be used as the example for this recipe. A sociologist working with an emergency room doctor is trying to see if there are any patterns in the distribution of children who enter emergency rooms with fevers. The research group is prepared with an Excel DBF4 table of the patients’ home addresses and a street network of Atlanta as their reference theme feature onto which the addresses will be geocoded. Their table of addresses is far from perfect and this recipe will guide you through the different pitfalls one might encounter when geocoding.



Methodology:
1) Open a New View and use the Add Data button



to add your reference theme feature (in this case, it is the street network of Atlanta, GA) After we added the street network, the view now looks like this:




2) Go to the project window and click on Tables.




Click Add and navigate to .dbf (the suffix for database files) file of address. Below is a screen shot of the .dbf we are using. Fields in the database include the patient record number, the patient address, zip code, symptoms when entering the emergency room, and the patient age.




3) Make the View1 window active by clicking on it. Go to the main menu bar and click View->Geocode Addresses. The Geocode Addresses window should pop up. Fill in the fields following the field labels.




Remember to select in which folder you would like to save your new geocoded address shapefile. Click the Folder button




and navigate to the appropriate directory (it may be helpful to save your new file in the same folder as your .dbf, but this is not required).




After you have selected your file location, click the Batch Match button




4) A window showing your geocoding results will pop up.




Because of errors in your address database, in this case it was in the patient1.dbf, you will get Partial or No Matches. Partial matches occur when the address record appears partially on the reference theme (e.g. the street name is correct, but the address number does not fit what is available in the reference theme). No Matches occur when there are gross spelling mistakes where the program cannot recognize the name, or other mistakes that would cause the reference theme to not recognize the address at all within the options in the reference theme. Information about these scenarios is included in the ArcView 3.2 Help Menu.

5) In this example we were able to match all addresses in the patient.dbf file except for one partial match and three that did not match anything at all. To view why the addresses did not match, click the Interactive
Re-match button




6) The Geocoding Editor should appear.




The editor displays the address shown in .dbf file of address, and below that, show the closest options available within the reference theme. You can either change your address entry if you find there is a mistake, or you can select one of the addresses the editor gives you. In this case, a 0 has been omitted from the address number. So we will change it from "167 W Peachtree" to "1670 W Peachtree".

After you are done with the adjustments, click the Match button.




7) After selecting Match, the editor will search through the reference theme once more and give you a new list of options. Usually, if there is a match, the correct one will be highlighted in yellow.
After you are done, click the Done button.

8) The Geocode Editor will then return you to the Re-Match Address Window showing you have now resolve the partial match address.





Next to Re-Match, scroll down the menu to select the No-Match option. Repeat the same procedure you executed with the partial matches to find the correct matches. Select Done when you have corrected all the un-matched addresses. If you are still having problems, See Pitfall 1.

9) After you have matched all the addresses correctly, the Re-match Address window should show 100% matches.




Click Done.

10) Within your View1, there should now be the added geocoded address theme. Click the box next to your new theme's name for the theme to display your geocoded points.



11) To change the look of your points, please see CSISS Cookbook section Cartographic Design.
Pitfalls:
Links:
ESRI Discussion Forum - For a discussion forum or FAQ list
ESRI Homepage -
ESRI Canada: K-12: Tutorial - see ESRI’s tutorial (this recipe references this page)
Authored by: Sam Ying Modified: 9/10/03


Copyright © 2002-2014 by Regents of University of California, Santa Barbara
Cookbook: Ben Sprague, Ethan Sundilson, Carlin Wong, Sam Ying