Geocode Street Addresses

 

Introduction

 

You will geocode 10 street addresses by using a reference street shapefile derived from the 2000 TIGER/Line file. The street addresses are stored in an ASCII file (cda_add.txt) as plain text. The street polyline shapefile (Kootenai_TIGERLINE.shp) provides the coordinate information for converting the address texts into point features. The reference street file must have attribute fields containing information that can be related to the text addresses. The procedures below show you how to do geocoding in ArcGIS.

 

Instructions

 

The sample data are available in the I:\Students\Instructors\Geoffrey_Duh\GISMarketing\Geocoding folder. Copy these data to your working folder in C:\Users before you continue.

 

  1. Double-click on the address text file to view its content. Add Kootenai_TIGERLINE.shp to ArcMap and view its attribute table. Parse the first record in the text file and fill the table below.

 

Address Field Name

Value

House Number

 

Prefix Direction

 

Prefix Type

 

Street Name

 

Street Type

 

Suffix Direction

 

Zone (Zip code)

 

 

  1. You will need an Address Location to do geocoding in ArcMap. Address locators use a specific process to find a location. First, the search parameter—often an address—is parsed into individual address components. Next, the address locator standardizes the address, defining the correct format of presentation. The address elements are then assigned to specific categories used in the search. The address locator then searches the reference data to find potential candidates. Each potential candidate is assigned a score based on how closely it matches the address. Finally, the address is matched to the candidate with the best score. To create an address locator for your specific address format, open ArcToolbox and start the Create Address Locator tool in the Geocoding Tools toolset.

 

  1. Set address locator style to “US Streets with Zone”, Kootenai_TIGERLINE.shp as the reference data, and role as Primary table. The US Streets with Zone style is closest to the geocoding style of Kootenai_TIGERLINE.shp.

 

  1. Use the table below to map the first 4 fields and accept default values for the others.

 

Field Name

Alias Name

House from left

FRADDL

House to left

TOADDL

House from right

FRADDR

House to right

TOADDR

….

Accept default values for others

 

 

  1. Specify an output name and click OK to process.

 

  1. When done, click the Tools menu in ArcMap, point to Geocoding, and select Geocoding Addresses. If the Address Locator you just created doesn’t show up, then click the Add button and add the Address Locator. Click OK to continue.

 

  1. Specify the cda_add.txt file as the address table. Note that the first line of the file is parsed as a field name record. Provide the name for the output shapefile or feature class. You can also take a look at the additional options of the geocoding tool. Click OK to continue.

 

  1. The Review/Rematch Addresses dialog shows that 9 out of 10 addresses are matched and one is unmatched. You can manually match the unmatched addresses to improve the match rate. Click the Match Interactively button to open the Interactive Review dialog. The dialog shows that the unmatched address is 2759 W Kathleen Ave and the Zip code is 83814. It turns out that the correct Zip code is 83815. Change the value in the Zone field to 83815 and click on any other field in the dialog. The Candidate field shows 21 candidates and their matching score. Select the one with a score of 100 (i.e., perfect match) and click Match button to match the address. The Status of that record now changes from U to M.

 

  1. Click Close to dismiss the dialog. The Review/Rematch Addresses dialog shows 100% of the addresses matched with score 80 -100. Click Done to dismiss the dialog. You can now see the 10 geocoded points on the map. This completes the geocoding process.

 

  1. For your own reference, you can check if the RLIS street layer can be used as the reference for geocoding.