AUSGeoid98 - geoid/ellipsoid separations (N values)

Note: This metadata describes the dataset in accordance with the ANZLIC (Australia New Zealand Land Information Council) Core Metadata Guidelines Version 2.

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Dataset citation

ANZLIC unique identifier: ANZCW0703005641

Title: AUSGeoid98 - geoid/ellipsoid separations (N values)

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Custodian

Custodian: Geoscience Australia

Jurisdiction: Australia

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AUSGeoid98 is the latest in a series of national geoid models for Australia. It uses the latest available data and techniques. AUSGeoid98 consists of a 2' by 2' grid (approximately 3.6km) of geoid-ellipsoid separations (N values) relative to the GRS80 ellipsoid, which is also used for the new Geocentric Datum of Australia (GDA94). These values are suitable for use with GPS and will improve the achievable accuracy of AHD height transfer using GPS. The format of the AUSGeoid98 data files is nearly identical to the superseded AUSGeoid93 data files. Full detail can be found at www.ga.gov.au/geodesy/ausgeoid/

ANZLIC search words:

LAND Geodesy Mapping

Spatial domain:

locality map

Geographic extent name: AUSTRALIA EXCLUDING EXTERNAL TERRITORIES - AUS - Australia - Australia

Geographic extent polygon: 112 -9, 154 -9, 154 -44, 112 -44, 112 -9,

Note: The format for each Geographic extent name is: Name - Identifier - Category - Jurisdiction (as appropriate) See GEN Register

Geographic bounding box:: North bounding latitude: -9 °; South bounding latitude: -44 °; East bounding longitude: 154 °; West bounding longitude: 112 °

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Data currency

Beginning date: 1998-11-01

Ending date: Not Known

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Dataset status

Progress: Complete

Maintenance and update frequency: As required

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Access

Stored data format:: DIGITAL - txt ASCII text document

Available format type:: DIGITAL - txt ASCII text document

Access constraints:

Data files and interpolation software may be downloaded from Geoscience Australia's website at www.ga.gov.au/geodesy/ausgeoid/ Interactive interpolation is also available. The use of AUSGeoid98 data files and interpolation software is encouraged and they may be downloaded at no cost. However, users may not charge others for the use of this data or software.

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Data quality

Lineage:

Several early versions of the geoid, in terms of the local Australian system, were available in the past (e.g. National Mapping Technical Report 13 "The Geoid in Australia - 1971, J.G. Fryer"), but these were replaced by global geoid models (e.g. OSU89, OSU91). These global models were refined for use in Australia in a series of Australian national geoids (AUSGeoid91, AUSGeoid93) leading to the current model AUSGeoid98.

AUSGeoid98 uses

- The complete expansion of the EGM96 Global Geopotential Model, which was produced by the US National Imagery and Mapping Agency (NIMA) and NASA's Goddard Space Flight Centre (Lemoine et al., 1997).

- The 1996 Australian Gravity data base from the Australian Geological Survey Organisation.

- Geoscience Australia / AGSO / National Heritage Commission GEODATA 9" Digital Elevation Model (DEM) (Carrol and Morse, 1996).

- Satellite altimeter derived free air gravity anomalies offshore, which were produced by Scripps Institute for Oceanography using a combination of several satellite missions. (Sandwell and Smith, 1997)

AUSGeoid98 is an outcome of an Australian Research Council grant (A49331318). This ARC group consisted of Associate Professor Will Featherstone & Dr John Kirby (Curtin University of Technology), Associate Professor A.H.W. Kearsley (University of New South Wales ), Professor John Gilliland (Univesity of South Australia), Prof Michael Sideris (The University of Calgary) and Rene Forsberg (KMS, Denmark)

Positional accuracy:

Exact in terms of the GDA94.

Attribute accuracy:

The absolute accuracy of the AUSGEOID98 N values is estimated to be better than 1/2 metre, while the relative accuracy has been estimated as 2-5 parts per million ( 2-5 mm per km).

Logical Consistency:

Not Applicable

Completeness:

Complete cover across Australia, including Tasmania and nearby offshore regions.

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Contact information

Contact organisation: Geoscience Australia (GA)
Contact position: Director, Sales and Distribution, ISB
Mail address: GPO Box 378
Mail address:
Locality: Canberra
State: ACT
Country: Australia
Postcode: 2601
Telephone: +61 2 6249 9966
Facsimile: +61 2 6249 9960
Electronic mail address: sales@ga.gov.au

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Metadata information

Metadata date: 2008-09-01

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Additional metadata

Metadata reference XHTML: http://www.ga.gov.au/meta/ANZCW0703005641.html

Metadata reference XML: http://www.ga.gov.au/meta/ANZCW0703005641.xml

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