Abstract

This dataset provides the spatially continuous data of the seabed sand content (sediment fraction 63-2000 mm) expressed as a weight percentage ranging from 0 to 100%, presented in 0.01 decimal degree resolution raster format. The dataset covers the Australian continental EEZ, including seabed surrounding Tasmania. It does not include areas surrounding Macquarie Island, and the Australian Territories of Norfolk Island, Christmas Island, and Cocos (Keeling) Islands or Australia's marine jurisdiction off of the Territory of Heard and McDonald Islands and the Australian Antarctic Territory. This dataset supersedes previous predictions of sediment sand content for the Australian Margin with demonstrated improvements in accuracy. Accuracy of predictions varies based on density of underlying data and level of seabed complexity. Artefacts occur in this dataset as a result of insufficient samples in relevant regions. This dataset is intended for use at national and regional scales. The dataset may not be appropriate for use at local scales in areas where sample density is insufficient to detect local variation in sediment properties. To obtain the most accurate interpretation of sediment distribution in these areas, it is recommended that additional samples be collected and interpolations updated.
Google map showing geographic bounding box with values North bound -8.8882 East bound 163.1934 West bound 109.2334 South bound -47.1982
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Product Type/Sub Type

dataset

Constraints

Creative Commons Attribution 4.0 International Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2011-01-01T00:00:00

Product Type

dataset

Topic Category

geoscientificInformation

GA Catalogue Number

71982 Product http://www.ga.gov.au/metadata-gateway/metadata/record/71982/

Keywords

GIS Dataset
National
marine jurisdiction
sedimentology
geoscience
mapping
seabed
National dataset
marine
AU-EEZ
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-8.8882
East bound
163.1934
West bound
109.2334
South bound
-47.1982

Lineage

Sediment samples were exported from Geoscience Australia's Marine Sediments database (MARS), an Oracle database developed by Geoscience Australia in line with ANZLIC data standards. A subset of this data was selected for use in predicting spatial distribution of sand content based on a set of criteria (similar to those reported by Li et al. 2010 and detailed GA record will be available in 2012). Predicting the spatial distribution of sand content at a 0.01 decimal degree resolution was undertaken by averaging the predictions of a combined method of random forest and ordinary kriging and of a combined method of random forest and inverse distance squared (the methods used is similar to that reported by Li et al. 2011 and detailed GA record will be available in 2012). The spatial interpolation method used was experimentally selected from over 40 methods/sub-methods based on assessment of predictive errors. The predictions were then imported to ArcGIS, and ArcGRID and ascii raster files were generated. Final raster files are in Geographic WGS 84 coordinate system with a 0.01 dd spatial resolution. File sizes are approximately is 79 MB (ArcGRID) and 135 MB (ascii) with dimension of 5396 x 3831 cells.

Digital Transfer Options

onLine

Distributor

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

Source Description

Source data not available.

Metadata File Identifier

a4c78d63-3040-0e18-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 SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Commonwealth of Australia (Geoscience Australia)
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
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