Abstract

These images are derived from the "Gravity Anomaly Grid of the Australian Region" (GEOCAT record: 67240). That grid combines accurate onshore gravity measurements, with satellite data over the offshore region. The cell values represent simple Bouguer anomalies at a density of 2.67 tonnes per cubic metre onshore and free-air anomalies offshore. The grid cell size is 0.5 minutes of arc, which is equivalent to about 800 metres.
Google map showing geographic bounding box with values North bound -8.0 East bound 170.0 West bound 100.0 South bound -52.0
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Product Type/Sub Type

dataset - Gravity Digital Data - Non-standard scale

Constraints

license
Creative Commons Attribution 3.0 Australia Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2008

Product Type

dataset

Topic Category

geoscientificInformation

Keywords

Gravity Digital Data
Non-standard scale
dataset
National dataset
gravity
geophysics
Gravimetrics

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-8.0
East bound
170.0
West bound
100.0
South bound
-52.0

Lineage

The gravity grid was derived from the complete onshore database as at May 2008 and marine gravity derived from satellite altimetry. A two-pass process was used to generate the grid from a composite file containing 1.4 Million land observations, 10.5 Million satellite values. For the satellite values refer to Sandwell, D.T. and W.H.F.Smith, Marine Gravity Anomaly from Geosat and ERS-1 Altimetry, J. Geophys. Research, 1997. The 0.5 minute grid is the finest mesh that is currently meaningful over the whole continent given that much of the data coverage is spaced at 4 or 11 km. The parameters of the grid are: Grid spacing: 0.5 minute = 0.0083333 degree (approx. 800 m) Projection: Rectangular in latitude and longitude Grid size: 8401 points longitude x 5276 points latitude Grid origin: 7 degrees 58.55 min south, 99 deg 57.35 min east (1,1) Scaling: Nil. Values are in decimal units (µms−² (micro metres per second squared)) Null value: -99999.0 Data accuracy: 5 units, maximum error 100 units onshore Data precision: 1 unit Gravity Datum: The gravity data as supplied are based on the AAGD07 datum. The gravity unit used is micrometres per second squared which is equivalent to 0.1 milligals. A filtered image was also created using a high-pass filter with a cutoff wavelength of 500 km. Images have a sunangle with illumination from the north east.

Digital Transfer Options

onLine

DISTRIBUTION Format

ers

Distributor

Role
distributor
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Metadata File Identifier

a05f7892-d805-7506-e044-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

Metadata Date Stamp

2014-02-14

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
Downloads
For information on acquiring this product,
please contact Geoscience Australia Client Services via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).