Australia is the world's smallest, flattest, and (after Antarctica) driest
continent, but at 7.7 million square kilometers (3.0 million square miles)
it is also the sixth largest country. Its low average elevation (300
meters, or less than 1000 feet) is caused by its position near the center
of a tectonic plate, where there are no volcanic or other geologic forces
of the type that raise the topography of other continents. In fact
Australia is the only continent without any current volcanic activity at
all - the last eruption took place 1400 years ago at Mt. Gambier.
The Australian continent is also one of the oldest land masses, with some
of its erosion-exposed bedrock age dated at more than 3 billion years.
More than one-fifth of the land area is desert, with more than two-thirds
being classified as arid or semi-arid and unsuitable for settlement. The
coldest regions are in the highlands and tablelands of Tasmania and the
Australian Alps at the southeastern corner of the continent, location of
Australia's highest point, Mt. Kosciusko (2228 meters, or 7310 feet.)
Prominent features of Australia include the Lake Eyre basin, the darker
green region visible in the center-right. At 16 meters (52 feet) below
sea level this depression is one of the largest inland drainage systems
in the world, covering more than 1.3 million square kilometers (500,000
square miles). The mountain range near the east coast is called the Great
Dividing Range, forming a watershed between east and west flowing rivers.
Erosion has created deep valleys, gorges and waterfalls in this range
where rivers tumble over escarpments on their way to the sea.
The crescent shaped uniform green region in the south, just left of
center, is the Nullarbor Plain, a low-lying limestone plateau which is so
flat that the Trans-Australian Railway runs through it in a straight line
for more than 483 kilometers (300 miles).
Two visualization methods were combined to produce this image: shading
and color coding of topographic height. The shade image was derived by
computing topographic slope in the northwest-southeast direction, so that
northwest slopes appear bright and southeast slopes appear dark. Color
coding is directly related to topographic height, with green at the lower
elevations, rising through yellow and tan, to white at the highest
elevations.
Elevation data used in this image were acquired by the Shuttle Radar
Topography Mission aboard the Space Shuttle Endeavour, launched on Feb.
11, 2000. SRTM used the same radar instrument that comprised the
Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR)
that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed
to collect 3-D measurements of the Earth's surface. To collect the 3-D
data, engineers added a 60-meter (approximately 200-foot) mast, installed
additional C-band and X-band antennas, and improved tracking and
navigation devices. The mission is a cooperative project between NASA,
the National Geospatial-Intelligence Agency (NGA) of the U.S. Department
of Defense and the German and Italian space agencies. It is managed by
NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth
Science Enterprise, Washington, D.C.
Location: 45 to 10 degrees South latitude, 112 to 155 degrees East longitude
Orientation: North toward the top, Mercator projection
Image Data: shaded and colored SRTM elevation model
Date Acquired: February 2000