O V E R V I E W

Geocode Services

Geocoding is the process of transforming a description of a location&emdash;such as a pair of coordinates, an address, or a name of a place&emdash;to a location on the earth's surface. You can geocode by entering one location description at a time or by providing many of them at once in a table. The resulting locations are output as geographic features with attributes, which can be used for mapping or spatial analysis.  

Geocode services provide the ability to assign locations to address attribute information. You can use a geocode service to:

• Assign a location to address attributes

• Generate a list of candidate locations for an attribute

• Assign address attributes to a location (reverse geocoding)  

• Modify input and output properties associated with the geocode process     

http://<Web Server Hostname>/<ArcGIS Instance>/services/<ServiceName>/GeocodeServer?wsdl
 

Working with geocode services that use ArcGIS 10 locators
 

The geocode process involves a number of steps.  Address input is packaged by a developer in a set of address fields for multiline geocoding or a single address field for single-line geocoding.  The geocode service parses the address into its address elements based on the style of the address locator.  The geocode service then uses the variations of the parsed address to match features within the locator.  The candidates that are generated are then scored based on weights, required fields, and spelling.  The matched location, match field values, and score are returned from the operation.

Working with geocode services that use pre-ArcGIS 10 locators

The geocode process involves a number of steps. The following diagram provides an overview of a simple geocode operation (call to GeocodeAddress) from the perspective of a geocode service. The address input is packaged by a developer in a set of address fields defined by the service. Some or all of the address fields are passed to an internal standardizer which standardizes, or parses, address content using a set of rules defined by a standardizer. Each parsed address item is associated with a match key. The match key relates address input and match fields in the reference data. The geocode service uses this relationship, one match field per reference data field, to generate a location. The score of the match is determined by the weights assigned to the match keys, required fields, and spelling sensitivities. The matched location, match field values, standardized address, and score can be returned from the operation.  

Geocode server methods and properties

The geocode server proxy includes a set of methods to initiate geocode operations and a set of methods to provide information about inputs and outputs to an operation. The chart below provides an overview of the all geocode server methods and their relationship to the role they serve. Input properties to geocode operations are returned from GetAddressFields, GetDefaultInputFieldMapping and GetLocatorProperties. For example, GetAddressFields returns a set of fields used to package an input address to most geocode operations. The geocode operations themselves are methods on the proxy. FindAddressCandidates returns many match candidates for a single address input. Geocode address returns the best match for a single address input. GeocodeAddresses locates a table of addresses and returns the best match for each input. StandardizeAddress returns an input address standardized using the geocode service standardizer. ReverseGeocode returns the nearest address to an input point.  A set of methods return information on the output properties from geocode operation results. The appropriate output methods are grouped with the geocode operation. For example, results from a call to FindAddressCandidates are packaged in a set of records whose field names and types are defined by GetCandidateFields.     

Methods