Authors / CoAuthors
Abstract
Laser DEM Shiny Colour Drape Images contains Digital Elevation Model (DEM) tiles covering the eastern half of Christmas Island as 8 bit TIFF, 24 bit TIFF, and ECW images. A LiDAR Digital Elevation Model (DEM) was constructed for the eastern half of Christmas Island from ground heights obtained from an airborne laser scanning survey flown September 2000 by AAM Surveys Pty Ltd. Shiny colour drape images of the ground surface were produced from this DEM in Geoscience Australia by processing the set of last returns (mostly ground heights), and the GPS location in MGA (GDA94) units of each height. Point shape files and Arc grids were also created from the raw data by GA. 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.
Product Type
dataset
eCat Id
66249
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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- DEM topographic
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- CX
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Topology
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- Published_Internal
Publication Date
2008-06-19T00:00:00
Creation Date
Security Constraints
Legal Constraints
Status
Purpose
Maintenance Information
notPlanned
Topic Category
elevation
Series Information
Lineage
In 2000 AAM surveys Pty Ltd. was commisioned by the commonwealth to fly an airborne laser scanning survey of Christmas Island (AAM_LaserDEM_readme). Raw data was tiled to shapefiles then converted to grids from which the LaserDEM shiny colour drape images were made. A wet look shiny colour drape algorithm was applied to each of the 27 '2000 LaserDEM Grid' tiles using ERMapper®, and the results saved as Tagged Image File Format (TIFF) images in both 8 bit (256 colour) and 24 bit (16 million colour) formats. Each wet look shiny colour drape DEM tile was also saved as an Enhanced Compressed Wavelet (ECW) image. The colour range has been optimized for each individual tile to provide maximum information. A consequence of this is that colours may not match at adjoining edges. Each image tile has a 1m pixel size. Most inland tiles and several coastal tiles are 2km x 2km in area. The inland tiles located at the edge of the flight path extent, and most coastal tiles, deviate from the 2km x 2km standard tile size as adjacent tiles have been merged to minimize areas of no data and ocean. An example of a 2000 LaserDEM shiny colour drape image can be viewed here. The advantage of the 2000 Laser DEM over previous DEMs is that the laser scanner used to produce the DEM was able to penetrate vegetation. Previous DEMs included the height of tree tops rather than the ground elevation obscured by vegetation. The 2000 Laser DEM therefore provides a more accurate and detailed picture of the ground surface of Christmas Island. Topographic features overgrown with vegetation are apparent on the 2000 Laser DEM shiny colour drape images, where in previous versions of CIGIS DEMs they were not (2000 Laser DEM views).
Parent Information
Extents
[-10.571, -10.412, 105.621, 105.715]
Reference System
Spatial Resolution
Service Information
Associations
Source Information
Source data not available.