ACT Geographic Data Directory
| ACT Geographic Data Directory |
| |
Note: This dataset description is metadata (data about data) which describes the actual dataset in accordance with the ANZLIC (Australia New Zealand Land Information Council) Core Metadata Guidelines
ANZLIC unique identifier: ANZAC0236001043
Title: DUS Corporate Geographic Database - Cadastral Postcode
Custodian: ACT Government, Department of Urban Services, Customer Service and Information, Information Management Branch
Jurisdiction: Australian Capital Territory
Abstract:
ACTPLA is the authoritative source custodian of the ACT's version of Australia Post Postcode areas. The cadastral postcode layer for the ACT Department of Urban Services Corporate Geographic Database (DUS CGD) contains a modified version of data from the authoritative Postcode table (ANZAC0236001043) sourced from the ACTPLA Spatial Database Management System (SDMS). The cadastral postcode layer has been created to specification under the DUS GIM Strategy and is included in the DUS CGD created under that strategy. The DUS CGD creates a fully homogeneous and integrated set of core geographic information which uses Oracle SDO. The CGD is a read only Oracle spatial database hosted within the ACT Government's production computing environment and is capable of being directly read by most GIS software. The CGD stores data in both the ACT Stromlo Projection and MGA94 projection for Zone55. This data set includes the following attributes: Postcode_ID (a persistent identifier), Postcode, ANZLIC_ID, Source_ANZLIC_ID, Feature_Type_Code, Create_Date, Area and Feature_Instance_Metadata_ID.
ANZLIC search words:
Spatial domain:
Geographic extent name: AUSTRALIAN CAPITAL TERRITORY - ACT - State or Territory - Australia
Note: The format for each Geographic extent name is: Name - Identifier - Category - Jurisdiction (as appropriate) See GEN Register
Beginning date: 2003-07-27
Ending date: Current
Progress: Complete
Maintenance and update frequency: Irregular
Access constraints:
This dataset has been classified as 'Community Access' by ACTPLA, the custodian of the SDMS POSTCODE table. See Lineage below. Community access data sets in the DUS CGD database are available for internal use by agencies in the ACT Government, including presentation though ACT Government web sites. Uses beyond this require prior approval by the custodians of both the authoritative source data (ACTLIC), and Department of Urban Services.
Lineage:
The CGD Postcode table has been created from data sourced from the POSTCODES and POSTCODE_POLYGONS tables in the ACTPLA Spatial Data Management System (SDMS). The original data was exported from SDMS (Oracle 8.1.6) with a selection on the attribute Current_Lifecycle_Stage to eliminate historic data not required for DUS business purposes. The lifecycle types which were preserved were Entered. This data was then imported into a translation table to enable some of the original attributes to be removed and verification checks to be performed. To ensure that the data was logically consistent, this table was converted through FME to a Shape file. This processes converts circular curves to a series of small chords, significantly increasing the number of vertices. This coverage was cleaned using a tolerance of 5mm and then generalised using the Douglas-Poiker algorithm with a 2mm tolerance to reduce the number of vertices and ensure alignment with the original data at a scale of 1:10 or better. The result was then converted back to Oracle Spatial using an Arc Coverage import to FME and further verification performed. Subsequently, for weekly data maintenance, a similar process is used to introduce incremental changes with retired instances transferred to a second version of the database. Contact the DUS IM Branch for further information on these processes.
Positional accuracy:
A prospective user should contact the custodian of the source data set (ACTLIC) for details of the horizontal accuracy. The errors introduced through the conversion process to this data set are less than 0.1m. The Z value is not stored.
Attribute accuracy:
The attributes are estimated to be correct at the 95% confidence level or better.
Logical Consistency:
The source data is managed by ACTPLA eliminate logical inconsistencies. Some minor variations may be introduced in the transfer process, however all geometry is then cleaned using ArcInfo software prior to transfer to the final Oracle Spatial format. The clean tolerance used is 5mm. Regions are created to ensure the completeness of multipolygons.
Completeness:
The data provided by the source custodian ACTPLA is managed and managed in a rigorous manner and is in a constant state of update. By arrangements with ACTPLA, automatic database triggers within SDMS write data updates to a holding database created for DUS to initaiate update of associated data on the CGD. The latest version of this data is used for each update. NOTE: The attributes of Source_ANZLIC_ID, Feature_Type_Code and Feature_Instance_Metadata_ID have not been populated.
Metadata date: 2007-11-30
Metadata reference: http://indexgeo.net/asdd/act/ANZAC0236001043.html
This dataset description can be discovered via the Australian Spatial Data Directory (ASDD)