Authors / CoAuthors
Unknown
Abstract
This dataset contains point, line and polygon topographic and cultural data for the Cocos (Keeling) Islands. Coverage is of Home and West Islands. To view a sample of the data showing the ArcView legend click here.
Product Type
dataset
eCat Id
81732
Contact for the resource
Custodian
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
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- GIS Dataset
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- AU-ACT
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2004-01-01T00:00:00
Creation Date
Security Constraints
Legal Constraints
Status
Purpose
Maintenance Information
asNeeded
Topic Category
geoscientificInformation
Series Information
Lineage
Obtained from LandInfo (Sinclair Knight Mertz) 8/12/99 who retained the data from a project previously undertaken by the Australian Surveying and Land Information Group (AUSLIG) for the Territories Office earlier in the decade. Lineage is not known prior to receipt by GA as no metadata was received. GA converted the DGN files received into ESRI Shapefiles and projected the files to CKIG92. Evaluation of the data suggests that the probable source coordinate system is Universal Transverse Mercator (UTM) Zone 47 (World Geodetic System 1972 (WGS72)). Using this input coordinate system, projection to CKIG92 resulted in a mismatch of coordinates. Using similarly digitised features in the coastlines, Geoscience Australia found that an X-shift (16.86mE) and a Y-shift (4.12mN) of the AUSLIG data resulted in a match with the cadastre for West Island. The files were renamed to reflect their content. Some features which were illogical were deleted (eg. Polygon contours, Runway lights labeled as golf tees). In December 2003, GA projected the topography data to UTM(WGS84) Zone 47S. Two coverages have been derived from the AUSLIG topography by Geoscience Australia in order to enhance the useability of the data in a GIS. These are a vegetation layer (vegetatn.shp) and a road centrelines layer (roads.shp). For GIS analysis using a road network, Geoscience Australia has created a road centreline layer based on the topographic data. This was accomplished using the ArcInfo 8.0.2 CENTERLINE command and then manually correcting (in ArcEdit) at intersections and elsewhere based on the original dataset and, to a lesser extent, the orthophotography. Converting to ArcInfo format necessitated dropping the third dimension from the data. Geoscience Australia did not attempt to digitise road features from the orthophotography where digital data did not exist. Users should be aware that the road centreline coverage is therefore incomplete. It would be useful if future work included the addition of further attributes (especially road names - which none of the available topographic and cultural data include). There are a number of features in the original topography data that do not have valid AUSLIG codes. Comparison with the orthophotography indicates that all these codes represent vegetation. Geoscience Australia has extracted these codes and created a polygon layer (in ArcInfo) by including common lines as well as those coded as a particular type. The resulting layer is coded according to the erroneous codes in the original data. Because the level of detail is different from the vegetation layers in the planning data, correlation was not conclusive. Re-coding according to actual vegetation types is recommended if this layer is to be used for analysis. The vegetation appears to match the 1987 orthophotography, and would therefore be out of date in some areas due to the fact that the 1992 planning data documentation reveals that areas have been cleared since the 1987 air photos.
Parent Information
Extents
[-12.24, -12.05, 96.8, 96.95]
Reference System
Spatial Resolution
Service Information
Associations
Downloads and Links
Source Information
Source data not yet available.