skip to content

Geocoding Tabular Data

Learning Objectives

  1. Identify methods in ArcMap to geocode tabular data by zip code and street names
  2. Apply interactive techniques to locate addresses
  3. Formulate and perform a batch geocoding procedure

Problem

A local event sponsor in Raleigh, NC puts on an art show exhibition in the downtown area every year to showcase the work of local artists.The Wake County Government has agreed to continually provide support for this event, as long as the function provides an attraction for its citizens throughout the County. To ensure effective planning for future shows, the sponsors have contracted a GIS professional to provide an analysis on where their program's attendees come from and to make recommendations for effective market reach in areas less-well represented in the Wake County area.

Analysis Procedures

To provide the analysis, ArcGIS for Desktop software was used along with data collected on past attendees and provided by local event sponsors.   Wake County zip codes, streets, and the county boundary layers were downloaded from the Wake County website to a folder called Wake_Geocode, and added along with an Excel file for attendees to the table of contents (TOC) in ArcMap.  This data was used for geocoding addresses by zip code and by streets within the county.  County map datasets were obtained as reference layers in order to create two Address Locator tools in which to geocode. Opening the ArcCatalog tab and right-clicking (RT-CLK) on this directory folder allows for creating a new Address Locator.  For geocoding by zip code, the existing US Address – ZIP 5-Digit address locator style was selected.  For streets, the existing US Addresses – Dual Ranges style was selected.  Next, the reference layers (Wake County datasets) were linked to the Address Locator by editing field mapping properties according to the chosen address locator style.  Fields such as zip code, street numbers, street names, and feature IDs are searched by the Address Locator according to the input field names within the address table (.xls file).  Before linking, the address table had to be modified for the Dual Ranges style requiring street numbers and names to be included in one field.  This was accomplished by exporting the Excel file to a DBASE table and using the Field Calculator.  A name was given to the newly created Address Locators.   The Geocoding Toolbar was used to then activate the Locators so that batch geocoding could begin.  Batch geocoding was initiated by RT-CLKing the attendees (database) layer and selecting the Geocode Addresses… command.  In the Geocode Addresses dialog box, address fields such as zip code or street were selected as inputs to the geocoding process.  Addresses located along the street features were offset on their respective side by 5 feet using the Geocoding Options button.  Individual addresses were located and labeled on the map using the Locations tab under the Find button of ArcMap’s Tools toolbar. 

 Once batch geocoding was complete, new shapefiles, or geocoded feature classes, were created to display point features of attendee residential addresses in ArcMap.  To determine which addresses were successfully matched, the shapefile was selected in the TOC and the Review/Rematch Addresses button selected on the Geocoding Toolbar.  This opened the Interactive Rematch dialog box, which showed the number of matched, tied and unmatched addresses, and where records from the geocoded feature class could be selected in the Geocoded Results panel, edited in the Address panel, and rematched from a list of potential candidates in the Candidates panel.   The Refresh or Rematch Automatically buttons prevent the user from having to re-geocode the entire table.  Flowcharts of the processes are shown below.

 

Attendees Geocoded by Zip Codes

 

Attendees Geocoded by Streets

 

 

Results

The resulting maps show the spatial distribution provided by geocoding, as well as match results.

 

Click images to enlarge.

 

Application and Reflection

Much like in the ESRI Online Modules, a map showing patterns of burglaries could be created by geocoding a database table that consisted of an address for each burglary.  From there, a density surface could be created showing concentrations of crime. 

 

Top of Page