Your everyday is filled with location questions: Where’s the nearest ATM? What’s the current temperature? Which is the fastest route to where I need to be from here?
The answers to all these questions rely on knowing where you are.
Yet pinpointing a location isn’t as straightforward as you may think.
Think of your favourite restaurant. How would you describe where it is? You could use the closest intersection, the building name, recognisable landmarks around it, the address or any other reference that makes sense to you.
But if other patrons of the restaurants were asked to describe where it is, would they use the same references as you?
This is what makes location so tricky – even at the address level, there is no single authority on how a place is described.
While having a well-defined location isn’t so critical when you’re just looking for a coffee, it definitely is if you are organising to get your electricity connected, or a quote for insuring your home, or you’re in trouble and need emergency services to come to you.
This is the challenge that led to the creation of G-NAF.
What is G-NAF
G-NAF is a database of all the physical addresses in Australia.
Because there is no single organisation that is responsible for assigning and collating addresses in Australia, G-NAF is built from addresses supplied by ten contributors including the land agencies in each state and territory of Australia.
As each contributor collects and stores addresses differently, the G-NAF production process involves independently examining and validating every candidate address, then textual and spatial matching.
Addresses from different sources found to be identical are merged into a single G-NAF record with feature level metadata capturing its linage and quality.
Through this process over 30 million contributed addresses are distilled into over 13.5 million G-NAF addresses.
More than just an address
G-NAF is a complex database consisting of more than 30 tables of data. For each of the 13.5+million principal addresses, the following additional metadata is provided to enhance the usability of G-NAF:
Principals and aliases
Sometimes a property has multiple addresses. For example, an apartment block that is sometimes listed with a ranged address (5-7 Smith Road) and sometimes as a single address (5 Smith Road).
The G-NAF production process produces information detailing the variations that exist between the addresses that people use and official principal addresses. The address provided by the custodian is considered the principal and any other addresses are known as aliases.
A geocode is a set of longitude and latitude values that enables the location of the address to be shown on a map. A geocode facilitates further manipulations, such as calculating the distance between the address and another point e.g. waterways for risk assessments; nearest delivery vehicle for job allocation; a specific shop for marketing purposes. Over 95% of addresses in G-NAF (including aliases) have an address level geocode.
Mesh block identifier
A mesh block is the smallest geographic region used by the ABS. The application of a mesh block ID to each G-NAF address (including a quality placement indicator) facilitates linkages to relevant demographic and socio-economic data.
Each address is given a confidence level to indicate how many contributors support it. Not all contributors are exposed to all addresses, for example, jurisdictional addresses may not cover all private estate and complex addresses.
If an address is no longer supplied by any contributor, it is given a negative rating and eventually removed from the database.
Primary and secondary
Addresses that contain sub-addresses, for example, a block of units or townhouses, have flags to denote the primary (e.g. 10 Smith Street) and secondary (e.g. Unit 6).
Unique persistent identifier
Each G-NAF address is allocated a unique persistent identifier, or the G-NAF PID, which enables information across different systems, departments or organisations to be shared based on a common address.
Due to the complex nature of G-NAF, PSMA works with a network of value-added resellers (VARs) that help organisations to use G-NAF most effectively to your specific business requirements. Check out our Experienced G-NAF Partners.
PSMA Partner Login
PSMA datasets are released in February, May, August and November.
Users with a commercial licence for PSMA Data can login here to request data updates.
G-NAF and Administrative Boundaries are also available from www.data.gov.au under open data terms. For more information, click here