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| Dataset | |
| Title | Cadastre |
| Custodian | Department of Land Administration (DOLA) |
| Jurisdiction | Western Australia |
| Description | |
| Abstract | This dataset contains polygon cadastral data and non-spatial attribute data for the Cocos (Keeling) Islands. Horsburgh Island and North Keeling Atoll are not included in this dataset. |
| Search Word(s) | LAND Cadastre LAND Ownership |
| Geographic Extent Name(s) | Cocos (Keeling) Islands |
| Data Currency | |
| Beginning Date | not known |
| Ending Date | 30DEC1999 |
| Dataset Status | |
| Progress | Complete |
| Maintenance and Update Frequency | not known |
| Access | |
| Stored Data Format | DIGITAL - ESRI Shapefile |
| Available Format Type | DIGITAL - ESRI Shapefile |
| Access Constraint | See contact details below. |
| Data Quality | |
| Lineage | Territories Office contract DOLA to maintain this data under
a 'Service Delivery Arrangement'. Prior to 1992 AUSLIG maintained the data on
behalf of Territories Office. February 2000: AGSO projected the data from Geographic (WGS84) to Cocos (Keeling) Islands Grid 1992 using ArcView 3.2a projection utility. Deleted erroneous polygons (large area, small visible extent) from shapefile after checking that they were spatially non-unique and contained no attributes. AGSO also joined Cocos ground audit data aquired as a DBF to the cadastre table. August 2000: AGSO moved all small islands between Home Island and South Island to match the orthophotography. This was done by manually editing the shapefile in ArcView 3.2 (XY-shift and/or Stretch). Islands which formed logical groups were moved/stretched as a group in order to minimise modification of the original data. August 2000: AGSO warped South Island and all nearby small islands to visually match the orthophotography (translation/rotation/stretching was not adequate). This was done using the ShapeWarp 2.2 ArcView Extension and a third-order polynomial fit on 28 Ground Control Points which resulted in an RMS Error of 4.58057. |
| Positional Accuracy | Absolute positional accuracy is not known. Because this is understood to be the islands' authoritative cadastre, the cadastre has been used as the reference dataset. Comparison with the Orthophotography and other datasets indicate that for islands other than the main islands, accuracy may not be as high as hoped. For South Island, prior to AGSO's warping it to match the orthophotography, mismatches with the orthophotography were up to approximately 45 metres. Following warping, mismatches are up to approximately 5 metres. |
| Attribute Accuracy | not known (The field A_Pin was assumed equivalent to the Pin field in the Ground Audit data and the tables were joined. For a discussion of AGSO's evaluation of Ground Audit attribute accuracy see the System Documentation). |
| Logical Consistency | This shapefile contains lines that denote cadastral boundaries. Through their use, it has been noted that the spatial content is complete and consistent in describing cadastral boundaries. Attribute data contains fields that are not completely filled however all records have a unique ID number. |
| Completeness | Appears complete for areas other than Horsburgh and North Keeling Islands. Attributes are apparently not complete (there are a lot of blank entries where, for GIS use, entries should not be blank). |
| Metadata Date | 24-07-2000 |
| Contact Information | |
| Contact Organisation | Department of Land Administration (DOLA) |
| Contact Position | Product Officer, Land Enquiry Centre |
| Mail Address | PO Box 2222 |
| Locality | Midland |
| State | Western Australia |
| Country | Australia |
| Postcode | 6936 |
| Telephone | (08) 9273 7344 |
| Facsimile | (08) 9273 7655 |
| Electronic Mail Address | Tony_Yeomans@notes.dola.wa.gov.au |
| Additional Metadata | |
| Projection | Cocos (Keeling) Islands Grid 1992 (CKIG92) - originally supplied as Geographic (WGS84) projection. |