I spent a lot of time at the post office this past holiday season. Each time I gave a package to the teller, he or she would enter the address into the computer to make sure it was valid – essentially a form of geocoding.
Geocoding is the GIS process of converting a street address into an XY coordinate. Since GIS stores data as XY coordinates, geocoding is extremely useful for converting lists of addresses into GIS features, thereby bestowing the power of GIS onto your data. Locations of customers, crime events, and delivery routes are a few examples where geocoding comes in handy.
What You Need to Geocode an AddressTraditionally, there are three things you need to geocode:
- A valid address
- Street data properly attributed for geocoding
- Address locator – a series of definitions and rules that tell the software how to use the street data to find the address
Some organizations maintain their own street data and devise their own address locators. If your organization doesn’t do this, never fear. Esri has tools that you can use for free to geocode individual addresses as well as lists or tables or multiple addresses.
One method calls upon the ArcGIS Online services that are integrated with ArcMap – Esri provides the data and the address locator through their web service.
The second method I will show you uses the Esri Streetmap data that is included with the Esri Data and Maps which you can download from your MyEsri.com account, provided you are an ArcGIS Desktop customer. Here, Esri provides the street data and the address locator which is stored on your computer.