A useful spin off of the soft photogrammetry is the opportunity to get one metre contours over the disturbed areas of the Island. For the north-east area of the Island 2km X 2km DEM contour tiles have been trialed in the CIGIS. Most are at a contour interval of 5 metres but tiles 2269 and 2469 have been done at a one metre contour interval. The DEM contours are surface contours. They pick up the reflective surface beneath the aircraft. The reflective surface may be the ground or it may be a dense vegetation canopy or rooftops etc. Further one metre contour coverage can be prepared on a cost recovered basis.

Laser DEM Grids consists of 27 digital elevation model grids. The Arcview grid files were constructed from the Airborne Laser Scanning shapefiles. The Laser DEM grid tiles cover the eastern portion of the Christmas Island. Each grid contains the height in metres of the ground surface with a value every one metre on the ground.

This is a national seamless data product aimed at regional or national applications. TOPO 2.5M 1998 contains a small scale vector representation of the topographic mapping features of Australia. The data include the following themes: Hydrography - drainage networks including rivers, lakes and offshore features; and Infrastructure - roads, railways, localities and built-up areas. Data was primarily sourced from Geoscience Australia`s GEODATA TOPO-250K data set however all features were revised in 1998. Free online and CD-ROM (fee applies).

Amino acid racemization (AAR) dating of the eolianite on Lord Howe Island is used to correlate several disparate successions and provides a geochronological framework that ranges from Holocene to Middle Pleistocene time. The reliability of the AAR data is assessed by analysing multiple samples from individual lithostratigraphic units, checking the stratigraphic order of the D/L ratios and the consistency of the relative extents of racemization for a suite of seven amino acids. Three aminozones are defined on the basis of the extent of racemization of amino acids in land snails (Placostylus bivaricosus) and 'whole-rock' eolianite samples. Aminozone A includes Placostylus from modern soil horizons (e.g. mean D/L-leucine ratio of 0.03±0.01) and whole-rock samples from unconsolidated lagoonal and beach deposits (0.10±0.01-0.07±0.03). Aminozone B includes Placostylus (0.45±0.03) and whole-rock samples from beach (0.48±0.01) and dune (0.45±0.02-0.30±0.02) units of the Neds Beach Formation, deposited during OIS 5. The oldest, Aminozone C, comprises Placostylus recovered from paleosols (0.76±0.02) and whole-rock eolianite samples (0.62±0.00) from the Searles Point Formation, which indicate the formation was likely deposited over several Oxygen Isotope Stages (OIS), during and prior to OIS 7. These data support independent lithostratigraphic interpretations and are in broad agreement with U/Th ages of speleothems from the Searles Point Formation and corals from the Neds Beach Formation, and with several TL ages of dune units in both formations. The AAR data reveal that eolianite deposition extends over a significantly longer time interval than previously appreciated and indicate that the deposition of the large dune units is linked to periods of relatively high sea level.

This document describes a format of the AVNIR-2 (Advanced Bisible Near-Infrared Radiometer) products generaged by the ALOS Data Processing Subsystem.

This dataset contains polygons that bound parts of Irvine Hill forest. The polygons were constructed by drawing lines that join points which were pegged out as being boundaries of the Irvine Hill area. The main points were supplied by Whelans. The line joins and polygon making process was done by Geoscience Australia. The shapefile containing the data is: forestedge_irvineh.shp. Details of the fields can be seen below: Field Type Width Decimal---------------------------------------------------Shape FIELD_SHAPEPOLY 8 0Area FIELD_DECIMAL 12 3Perimeter FIELD_DECIMAL 12 3Plot3pef2_ FIELD_DECIMAL 11 0Plot3pef2_ FIELD_DECIMAL 11 0Entity FIELD_CHAR 14 0Layer FIELD_CHAR 32 0Elevation FIELD_DECIMAL 18 5Thickness FIELD_DECIMAL 18 5Color FIELD_DECIMAL 11 0Pointnumbe FIELD_DECIMAL 11 0Pointheigh FIELD_DECIMAL 18 5Pointcode FIELD_CHAR 8 0Sourcethm FIELD_CHAR 16 0Hectares FIELD_DECIMAL 16 3

Digital orthophotography was prepared from aerial photography flown on the 16th, 20th, and 21st of August 1987 and the 1st September 1987 by the Australian Survey Office (now Geoscience Australia) Canberra. AGSO commissioned BHP Engineering, Land Technologies Division to generate orthophotography from the 1987 aerial photography as a component of this Christmas Island GIS project that AGSO undertook on behalf of Territories Office. The orthophotography has a 30cm on-the-ground pixel size. The quality and resolution of the orthophotography is reasonable down to 1:500 scale. An orthophotograph is a computer image of an aerial photograph in which various distortions due to the landscape and camera lens have been removed. This data is based on the aerial photography of Christmas Island flown in August and September 1987. This has been converted to detailed colour orthophotography (at a 30cm ground resolution) presented as one hundred and fifty-seven 1km tiles for the whole of the Island. On most systems not all the orthophotography will be in this directory, due to limitations of disk size. Most orthophotography of disturbed areas (mining or township) is on the core CD-ROM.

The pinnacle field boundaries dataset covers the whole of Christmas Island. It contains polygons that have been digitised around areas or fields of pinnacles. The polygons were digitised in two goes. The first was a animated process initiated by Geoscience Australia using Erdas software, this resulted in high resolution polygons located over the north east portion of Christmas Island. This turned out to be a slow process so the task was then taken up by manual digitising off the screen using orthphotography as a back drop. This method was used in digitising the rest of the island. The lack resolution for these polygons can be seen by their blocky appearance, these are visible at scales of 1:10,000. The pinnacle boundaries shapefile is pinclbnd.shp and contains the following fields: Field Type Width Decimal ---------------------------------------------------Shape FIELD_SHAPEPOLY 8 0 Area FIELD_DECIMAL 12 3 Perimeter FIELD_DECIMAL 12 3 Altpinn_cn FIELD_DECIMAL 11 0 Altpinn_cn FIELD_DECIMAL 11 0 Single_tre FIELD_CHAR 16 0 Dxf_color FIELD_DECIMAL 2 0 Dxf_thickn FIELD_DECIMAL 12 3 Dxf_type FIELD_CHAR 10 0 Dxf_elevat FIELD_DECIMAL 12 3 Dxf_angle FIELD_DECIMAL 12 3 Dxf_size FIELD_DECIMAL 12 3 Dxf_text FIELD_CHAR 80 0 Dxf_attrib FIELD_CHAR 16 0 Dxf_iid FIELD_DECIMAL 11 0 Hectares FIELD_DECIMAL 16 3

Airborne Laser Scanning contains ESRI shapefiles constructed from ground height data points. The heights were obtained from an airborne laser scanning survey conducted by AAM Surveys Pty Ltd. The shapefiles contain surface heights in metres for the eastern half of Christmas Island.

This dataset shows the approximate flight lines and centres of the aerial photography in relation to Christmas Island