Geocoding with ESRI Technology

 

ArcGIS has an in-built geocoding capability that can be customised to suit address structures and reference databases from any country.  In brief, a user needs a reference database of addresses to match against and a set of geocoder definitions or rules that define how an input address is parsed and then subsequently matched against the reference databases.

Reference Data

NAVIGATE uses the G-NAF (Geographic National Address File) product from PSMA Australia as the source for the reference databases. The G-NAF contains approx 13 million addresses and geocodes and is delivered to NAVIGATE as a highly normalised data model that includes a number of data tables and a series of associated look-up tables.

This structure is not suitable for immediate use with the ArcGIS Geocoder as reference data. NAVIGATE has taken the complex structure of the G-NAF and generated single, flat tables that contain all the necessary details for geocoding and is in a suitable format for use as reference data with the ArcGIS geocoder. This table is derived by querying the numerous G-NAF tables and adding a point geometry from the longitude and latitude supplied on the G-NAF record.

NAVIGATE Rule Base Customisations

NAVIGATE has reworked the out of the box rule base definitions (designed for North American addressing conventions and syntax) using the ESRI Geocoder Development Toolkit. We now publish a series of Australian rules and definitions (called locators) for the ESRI ArcGIS Geocoder which refer to the G-NAF reference data.

Our Australian address pattern and locator files result is up to 15% - 20% improvement in address parsing and subsequent matching to the reference data. Examples of improvements using GDK Customised to Australian address syntax include:

·        2/85 George St (2 George St with standard address parser)

·        10-12 Clarke St (1012 Clarke St with standard address parser)

·         St Kilda Rd (Saint Kilda Rd with standard address parser)

·        10 West End Pde (10 W End Parade with standard address parser)

·        Support for "The Corso," "The Avenue," Etc..

Geocoding Product Structure

The NAVIGATE Geocoding kit for feature based geodatabases or SDE consists of

a)               a set of three feature datasets, each holding one feature class of reference data, indexes and internal geocoding rules base (termed a locator).

a.     Feature class 1 is a set of geocoded street address and suburbs

b.     Feature class 2 is a set of geocoded street addresses with an alternative suburb name

c.      Feature class 3 is a set of geocoded street segment centrepoints (within a suburb)

b)               an external file or locator that calls these feature datasets in sequence.

ArcGIS reads the input addresses, parses the structure as per the rules bases and then attempts to find a matching address in the first feature dataset. If the address cannot be found there the process cascades to the second reference set and then the third. 

Geocoding in ArcGIS with the NAVIGATE G-NAF Geocoding Kit
Schematic Diagram