Land Cover and Land Use

Sub-Theme

National Topographic Data

Custodian 
Geoscience Australia
Aggregator 
Geoscience Australia

National Topographic data – principally referred to in this document as Geodata Topo 250K Series 3 – is a nationally consistent representation of natural and built environment features on the earth's surface for Australia excluding external territories. The data is thematically ordered and includes the following datasets containing up to 92 different feature classes:

  • Culture
  • Drainage
  • Elevation
  • Framework
  • Habitation
  • Transport
  • Utility
  • Vegetation

National Datasets in this Sub-Theme

National Topographic Data

Purpose

The purpose of National Topographic data is to provide nationally consistent fundamental information depicting the natural and built environment. This information is used by Commonwealth, State & Territory governments as well as industry and the public to assist and inform decision making across a diverse range of activities including: emergency management, environmental monitoring, infrastructure development, urban planning, resource exploration, recreation and the establishment of legal boundaries and land ownership.

Dataset Uses

Topographic data depict the natural and built environments of the earth's surface and are a critical input for a range of uses:

  • Emergency management
  • Risk assessment
  • National defence and border protection
  • Infrastructure planning and protection
  • Navigation and route planning
  • Recreation
  • Education
  • Mineral and energy exploration
  • Environmental monitoring

With reference to Land Cover the topographic information depicting built environment data, such as built-up-areas, are used to support the classification of urban areas.

Access and Licensing Details

Products and Services relating to this dataset are made available under open access policy and guidelines. Creative Commons Attribution 3.0

Quality

Geodata Topo 250K Series 3 is primarily sourced from Geodata Topo 250K Series 2 and 1:250 000 scale map reproduction material (from the National Topographic Map Series and Defence Joint Operation Graphics). A key revision source for the data is satellite imagery taken from the SPOT Panchromatic and LANDSAT Thematic Mapper Sensors.

Positional accuracy:

  • Horizontal accuracy: The summation of errors from all sources results in data with a standard deviation of 85 metres for well-defined features. As the data were digitised from existing map production material, some features may be subject to cartographic displacement.
  • Vertical Accuracy: Most spot heights have an accuracy of + or - 5 metres, however bench marks and horizontal control points have an accuracy of + or - 1 metre. The accuracy of contours is defined as 1/2 of the contour interval, for example + or - 25 metres for a 50 metre contour interval.
  • Attribute accuracy: The allowable error in attribute accuracy ranges from 0.5% to 5%, at a 99% confidence level. Where less than 1% of attribute errors are permissible the entire population is tested. Where a less stringent limit is set for allowable errors a random subset of the relevant features in the tile is generally tested. The sample size is determined from statistical tables using the known population size of the relevant feature.
  • Logical Consistency: Validating logical consistency may involve tests to check that table and file names are set out as in the Data Dictionary. Also included are graphical tests which check such things as intersections, polygon closure, minimum sizes of polygons and topological relationships. The allowable error in logical consistency ranges from 0% to 5%.
  • Completeness: All instances of a feature and its attribute values that appear on the source material are captured unless otherwise indicated in the criteria for that feature.

Current Status

Revised regularly up to 2006 as part of the 1:250,000 scale topographic mapping program from satellite imagery and information supplied by automobile associations, local government, tourist information and other volunteered information.

There is currently no single vertical integration of all seven land cover datasets, as listed, for the national coverage.

Future Status

Provide a nationally consistent suite of land cover datasets which support and deliver land cover information. This will allow linking of location of these features across all themes.

Key Users

Federal, State and Territory Government Departments, industry and research communities.

Version

1.00

Details