One of the requirements for a computerised Land Information System is that each parcel can be uniquely identified.

In the South Australian system, parcels are usually identified by the combination of a plan and an allotment in the plan. In residential areas this is often a Deposited Plan number (eg: D12345) or Filed Plan number (eg: F12345) and an allotment number (eg: A1). Images of these plans can be obtained directly through a Plan Order search on PIERS Online except for Filed Plans with numbers greater than 100 000 (see explanation below).

However in much of the state, especially rural areas, many parcels are identified by the original crown division of the land into Sections within Hundreds or Allotments within Government Towns.

A property search from PropertyAssist and the land parcel maps in the Property Location Browser show the parcel identity as a plan component and parcel component.

• Sections in Hundreds can be identified by a plan component beginning with 'H' and a parcel beginning with 'S', where the plan number is a code that designates a Hundred name. There are also 'Blocks' within Hundreds that are identified by a parcel component beginning with 'B'.
• Allotments in Government Towns can be identified by a plan number beginning with 'T' and a parcel beginning with 'A', where the plan number is a code that designates the Government Town name.

In these cases it is necessary to use the Hundred/Parcel search or Govt. Town/Allot search on PIERS Online to obtain a list of plans. The property boundaries for these parcels may be on more than one survey plan and professional advice should be sought in the interpretation of measurements shown on survey plans.

There are other plan and allotment types within the Land Information System including Closed Roads and Town Acres within the City of Adelaide.

Filed Plans with numbers exceeding 100 000 were created from Certificate of Title diagrams as a means of uniquely identifying parcels with duplicate parcel identifiers. Typically these would have been previously designated as duplicated 'part' allotments in a Deposited Plan. Copies of these plans are obtained from the Product Ordering facility in the PropertyAssist website.