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: ANZAC0236001047
Title: DUS Corporate Geographic Database - Reference Contours
Custodian: ACT Government, Department of Urban Services, Customer Service and Information, Information Management Branch
Jurisdiction: Australian Capital Territory
Abstract:
There are three tables in the Department of Urban Services Corporate Geographic Database (DUS CGD) covered by this metadata record. They have been created to the specification agreed to as a part of the DUS GIM Strategy and included in the Corporate Geographic Database (CGD) created under that strategy. The DUS CGD creates a fully homogeneous and integrated set of core geographic information which uses Oracle SDO. The DUS CGD is a read only Oracle spatial database located in 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. The tables included in this metadata statement are Contour_Half_Metre, Contour_Two_Metre and Contour_Ten_Metre. The first two of these were created from source data provided by ACTLIC. The third table was created from data provided under license to the Department of Urban Services by the NSW Department of Land and Property Information. These data sets includes the following attributes: Contour_ID (a persistent identifier), Elevation, 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: As required
Access constraints:
The CGD has been compiled as a part of the DUS GIM Strategy. Community access data sets in the database are available for internal use by agencies in the ACT Government, including presentation through ACT Government web sites. Use outside of this should be approved by the custodian of the source data (ACTLIC in the case of the Two and Half Metre Contour data sets). These two data sets are classified as Community Access. Please refer to the GIM Unit for details on the Ten Metre data set.
Lineage:
The source data for the Two and Half Metre Contour data sets was provided by ACTLIC in Shape format. The lines in these files were broken where the data was used for presentation purposes so that the contour height value could be printed clearly. The files were read into ArcInfo and cleaned with a tolerance of 5mm to remove the occasional artefact. They were 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 to Oracle Spatial using an Arc Coverage import to FME. Further verification was performed at this stage. The Ten Metre Cotours were provided by LPI as ArcInfo export files in AGD Geographic coordinates for individual 1:25,000 map sheets. Those files required to give coverage over the ACT were selected and merged into a single ArcInfo coverage. This was projected to ACT Stromlo projection and processed to alter the attributes to meet the CGD standard. The resulting coverage was then cleaned and converted to Oracle Spatial using an Arc Coverage import to FME. Further verification was performed at this stage.
Positional accuracy:
A prospective user should contact the custodian of the source data set (ACTLIC or LPI) 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:
All three data sets have been cleaned and generalised using ArcInfo with tolerances of 5mm and 2mm respectively. The lines for the Two and Half Metre Contours have been broken at source to allow for the display of height values. These breaks have not been joined again in this data set.
Completeness:
The Half Metre Contour data set extends over a limited area of the ACT. It includes the area bounded by the Barton and Federal Highways extending to the northern boundary of the ACT. It also covers the areas with potential to be developed to the North and West of Belconnen. The Two Metre Contours data sets covers the whole area from Tharwa north. The 10 Metre Contour data sets covers the whole of the ACT. 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/ANZAC0236001047.html
This dataset description can be discovered via the Australian Spatial Data Directory (ASDD)