There are several steps, known as the geocoding workflow, that should be followed for successful geocoding. These steps are outlined below.
1. Build or obtain reference data
Obtain and make any needed modifications to the reference data to coincide with the address locator style requirements.
2. Determine address locator style
Select an address locator style that accommodates the type of data you want to geocode and the attributes available in the reference data.
3. Build an address locator
Based on a specific address locator style, create an address locator and specify the geocoding options.
4. Locate addresses
Using your address locator, search for an individual address, place name, or locational-based information. The address locator can also be used to geocode a table of addresses.
5. Publish or maintain your address locator
The address locator can be shared as a locator package or published as a geocode service. If the reference data is updated, the related address locator can be rebuilt.
Build or obtain reference data
Initially, the geocoding process requires two types of information, reference data for creating an address locator and address data for matching. Reference data refers to a geographic information system (GIS) feature class containing the address attributes you want to search. For example, when searching for house number addresses, the reference data must contain the house number ranges, street names, or address attributes of the specific parcels. In assessing whether the reference data that you have will work for your geocoding process, there are a few points to consider based on the extent and resolution of the data.
The reference data needs to cover the same area that you want to geocode. For example, if you are attempting to geocode cities across the entire continental United States, reference data that only presents features in the western states will not perform the task. Each address that you want to geocode must be present in your reference data. This leads to the second property of the reference data, the resolution.
Beyond determining that the data has a spatial coverage that includes all the features you want to geocode, you must also consider whether the reference data has information at the detail that you want to search. If you want to geocode individual addresses, you need to be sure that your reference data has information of the essential address components. If your reference data only contains street names and not address ranges for each street segment, you will not be able to pinpoint the exact location along that street where the address is located.
Determine address locator style
The address data refers to the individual or group of addresses you plan to geocode. The address data also needs to comply with certain formats. The specific requirements of the address data are based on the elements of the address locator style that you intend to use. In general terms, the address data needs to contain the desired elements used in matching an address to a feature and must be in an acceptable format.
To correctly geocode, it is important to understand the variety of address locator styles and select the one that best matches your address and reference data.
Build an address locator
Once an address locator style has been selected and reference data has been prepared for that style, you are ready to build an address locator.
An address locator contains a snapshot of address attributes and indexes provided from the reference data and a set of properties specific to the selected address style. After an address locator is built, addresses can be matched against the address locator. The reference data will be disconnected from the locator. If the reference data is updated, you can rebuild the locator to refresh the information.
Sometimes, you might have a number of address locators that come from different sources or cover different types of features. If you want to geocode the addresses against all the individual address locators you have, you can create a composite address locator so that addresses can be matched against the multiple address locators and find best matches.
ArcGIS provides two methods for locating addresses: one for finding individual addresses and one for finding locations for a table of addresses, commonly referred to as batch geocoding.
There are several basic steps to locating addresses. This process includes breaking down the input address into components, finding candidate locations, assigning match scores to the locations, and narrowing down the best candidate.
Publish or maintain the address locator
Once you have created an address locator, there are several optional tasks that you may do. These include the sharing or publishing of the address locator, or maintaining the reference data and updating the related address locator.
Sharing your address locator as a locator package
Address locators and composite locators can be packaged and distributed by creating a locator package. Creating a locator package is a process of copying and compressing the locators into a single file (.gcpk). The package file can then be shared easily through file transfer or with any other ArcGIS users via ArcGIS online.
Publishing your address locator as a geocode service
Another way to share your address locator is to publish the locator as a geocode service to a GIS server. The service can be used by others on the web or on other client applications.
Maintaining the address locator
When you initially create your address locator, the address locator contains a snapshot of the reference data at the time of creation. However, like most data files, your reference data may require frequent updates.
The addition of streets to the feature class, changing street names or zone properties, or simply improving the accuracy of the geometry of the features all justify modification to the geocoding reference data. When these changes are made to the reference data, you can rebuild the address locator to reflect these changes. If you opt not to rebuild the address locator, geocoding continues to function with the existing locator. It produces geocoding results based on the state of the reference information when the locator was created.