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Northeast Pilbara geological digital data. Digital geology of Marble Bar, Port Hedland, Nullagine and Yarrie

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


Dataset citation

ANZLIC unique identifier: ANZCW0703002525

Title: Northeast Pilbara geological digital data. Digital geology of Marble Bar, Port Hedland, Nullagine and Yarrie


Custodian

Custodian: Geoscience Australia

Jurisdiction: Australia


Description

Abstract:

These data are a digital representation of information depicted on printed maps from the Australia 1:250, 000 Geological Series produced by AGSO and the Geological Survey of Western Australia (GSWA) between 1972 and 1982. The data are gridded according to the standard Australian 1:250, 000 sheet breakup. The complete dataset is comprised of the 4 1:250, 000 sheets covering marble Bar, Nullagine, Yarrie and Port Hedland in Western Australia.

Data present include geological polygons (stratigraphic units), linear structural features (faults,

dykes, folds, trends, lineaments etc).

Polygons have a range of attributes extracted from each individual map including unit name, age and lithology, while lines and points are feature coded according to the AGSO publication Symbols Used On Geological Maps' (BMR 1989). A standard look-up table of AGSO geological codes and descriptions is available. Pilbara Data has gradually evolved from elementary 'CAD' quality data into its present topologically structured GIS format, and hence has many imperfections and inconsistencies. The spatial accuracy of data from some older maps is particularly problematical. Data has undergone only moderate checking. These map sheets were originally compiled on poor topographic bases. For a more accurate coverage of geology, use the adjusted digital version.

ANZLIC search words:

  • GEOSCIENCES Geology Mapping
  • GEOSCIENCES Geology Maps

Spatial domain:

locality map

Geographic extent name: SF50-4 PORT HEDLAND - SF50-4 - 1:250 000 Map Series - Australia

Geographic extent name: SF50-8 MARBLE BAR - SF50-8 - 1:250 000 Map Series - Australia

Geographic extent name: SF51-1 YARRIE - SF51-1 - 1:250 000 Map Series - Australia

Geographic extent name: SF51-5 NULLAGINE - SF51-5 - 1:250 000 Map Series - Australia

Geographic extent polygon: 118.5 -19.91, 121.5 -19.91, 121.5 -22, 118.5 -22, 118.5 -19.91,

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

Geographic bounding box:
North bounding latitude: -19.91 °
South bounding latitude: -22 °
East bounding longitude: 121.5 °
West bounding longitude: 118.5 °

Data currency

Beginning date: Not Known

Ending date: Not Known


Dataset status

Progress: Complete

Maintenance and update frequency: Not Known


Access

Stored data format:
DIGITAL - dgn MicroStation Design Graphic Network (DGN) MicroStation
DIGITAL - ArcGIS-coverage ArcInfo coverage Lambert Conformal Conic WGS84
DIGITAL - ArcGIS-coverage ArcInfo coverage Universal Transverse Mercator (UTM) WGS84
Available format type:
DIGITAL - e00 ArcInfo export (e00) ArcInfo Workstation
DIGITAL - dat Data file MapInfo
DIGITAL - shp ArcView shape file ArcView

Access constraints:

Licence required.

Free Data Download

Data quality

Lineage:

Source maps: the geological maps are a depiction of information acquired from interpretation (mostly airphoto), field observation, and subsequent investigation (eg sample analysis for age and rock-type determination) . Some detail may have been generalised, repositioned, or omitted from the primary data for cartographic purposes. Maps were colkoiled from unrectified photo overlays onto topographic bases supplied by Australian Government mapping authorities. Drainage and, where necessary, other topographic features (eg fence lines) were used for spatial control of the geological data (see POSITIONAL ACCURACY). PILBARA Data: data were captured from stable-base repromat used in the production of the hardcopy multicolour geological maps. Initial acquisition was by high precision scanning. Resultant raster files were warped to fit digital graticules generated using Intergraph CAM software. Affine-'- warp was used, with the four corners of each tile forming tie points. Warped raster files were then vectorised and cleaned up using Abakos Provec and Scanfix software. Further interactive editing and additional capture of Doir-t data (via data heads-up digitising over the warped raster images) was carried out using MicroStation (V4.4.023) software. Data on some tiles were block shifted to account for datum/spheroid changes (See ADDITONAL METADATA for more information). MicroStation vector data were plotted and visually checked prior to conversion to IGISI format. No attribution was attached to the MicroStation data. MicroStation vector data were translated to Arc/Info coverage format using in-house scripts and ESRI's IGDSARC utility. Attribute fields were populated using information from the printed maps and coverages were built, checked and edited. The 60 individual 1:250, 000 sheets were then all put into one geology coverage, the duplicate frames were deleted and a new graticule was created in ARC to replace the frame arcs. Extra attributes were also added.

Positional accuracy:

An accurate assessment of horizontal accuracy is not possible because the history of the original source information and subsequent revisions by the States is not fully known. However during construction of the dataset we observed a range of errors/anomalies which we believe may be due to: (i) inaccurate topographic bases, (ii) spheroid/datum differences, (iii) map production processes.

Attribute accuracy:

Attributes are mostly a representation of information on the source maps and should be viewed in that context - some of the information/interpretation is up to 30 years old and may be incorrect/outdated. Attributes are tile specific - for example the same geological unit on separate tiles may have different lithological descriptions, ages and possibly even names. This is a reflection of the knowledge/-.nformation available at the time of production of the source map.

General: geological units and linear structures such as faults and folds were largely interpreted

from airphotos in conjunction with field observation/measurement, and sample collection and

analysis. The reliability diagram on the printed geological source maps gives some

(basic) indication of the level of work undertaken. Most of the source maps have accompanying Explanatory Notes which provide much more detail about the geology and interpretations. (maps were subject to considerable checking and editing during their production, and can be considered a good facsimile of the primary data).

Logical Consistency:

Data have been checked visually on plots and for topological consistency using in-house routines and Arc/Info GIS software. As such as possible, every effort has been made to ensure that the accuracy and standards of the source maps have been maintained.

Completeness:

Coverage: Pilbara maps are essentially lithology maps and therefore not all rock units have a name. Their names are observed they have been extracted from AGSO's Oracle database.

Classification: completeness and consistency of classification needs to be considered in the context of the time span of the source geological maps (1972-1982) and the highly interpretative nature of the discipline. Broadly similar classification, and measurement techniques have been applied to geological map compilation for many years, however resultant data does reflect individual geologists' ideas and preferences. The classification of boundaries, faults etc (accurate, approximate, concealed, inferred) for example is not particularly consistent and therefore needs to be treated with caution. Additionally, maps produced since the early 1980's will have been subject to more field checking, and may have had the advantage of remotely sensed data (Landsat, SPOT, and geophysical images). In general, one can say that modern maps (and hence the digital data derived therefrom) contain significantly more detail (are less generalised and have greater subdivision of geological units) than older maps.

Verification: there is no consistent record of the extent of field observation as opposed to remote (airphoto) interpretation. More information can be found in Explanatory Notes which were produced in conjunction with the geological maps.


Contact information

Contact organisation: Commonwealth of Australia (Geoscience Australia) (GA)
Contact position: Manager Client Services
Mail address: Cnr Jerrabomberra Ave and Hindmarsh Dr
Mail address: GPO Box 378
Locality: Canberra
State: ACT
Country: Australia
Postcode: 2601
Telephone: 02 6249 9966
Facsimile: 02 6249 9960
Electronic mail address: sales@ga.gov.au

Metadata information

Metadata date: 2013-03-08


Additional metadata

Metadata reference XHTML: http://www.ga.gov.au/meta/ANZCW0703002525.html

Metadata reference XML: http://www.ga.gov.au/meta/ANZCW0703002525.xml

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Authors:Blewett, R.S.
SPATIAL INFORMATION FOR THE NATION