���˾þ�

Flying high above the terrain of central Australia, you can pick out old
river systems, and the location of ancient coastlines. This is all now possible
by computer, using three-dimensional visualisation software and a new CD-ROM
from the Australian Surveying and Land Information Group (AUSLIG) and the
Australian Geological Survey Organisation. The two Federal Government agencies
have combined their data on elevation and topography to create the CD-ROM, known
by catchy name of GEODATA 9 Second DEM. The CD contains a regularly
spaced grid of more than five million elevation points about 250 metres (9
seconds) apart across Australia. This digital elevation data can be used by
software packages, such as geographical information systems (GIS), to build a
three-dimensional platform of the Australian terrain onto which other data can
be mapped. For instance, geophysicists can lay remote sensing data on top of the
elevation data to indicate the location of minerals with respect to physical
features. GEODATA 9 Second DEM can be obtained at AUSLIG regional
offices and data distributors. It is sold in 37 blocks or tiles, each covering
about 6 degrees longitude and 4 degrees latitude or about half the size of
Victoria. The cost is $250 a tile or $5500 for national coverage.
For more information see the AUSLIG website on http://www.auslig.gov.au