Topography refers to the features and forms of a land surface. Topographic information is used for multiple reasons depending on the purpose of the application. These include urban planning, emergency management, mining, surveying, and recreational uses.
The Australian continent is divided into four primary topographic regions.
The low sandy eastern coastal plain
The central plains
The eastern highlands
The western plateau
Most of the mountains on the Australian continent have eroded over time with only about 6% of the whole continent currently above 2000ft (600m). The average elevation is below 1000 feet, and the highest point here is Mt. Kosciusko, 7,310 ft (2,228 m) which is at the south-eastern part of New South Wales. The lowest is Lake Eyre in South Australia, which is 49 feet below sea level. Australia is one of the oldest geologies in the world with grains of rock found in West Australia in 1983 dated to be around 4.1 to 4.2 billion years old, making them the oldest to be found on Earth.
The only permanent river system, which without a doubt is also the most important one, is formed by Murrumbidgee, Darling, and Murray rivers in the southeast. The largest river in Australia is the Murray River which flows right from the Australian Alps in New South Wales to the sea below Adelaide in South Australia, covering a distance of 2600km. There are other important rivers as well, but they are relatively ephemeral as they flow in abundance during the wet season and remain dry for other parts of the year. The largest lakes here are without outlets and dry up after the wet season as well.
The coastline contains only a few capes or bay, making it relatively smooth and there are major sea inlets – in the south, the Great Australian Bight and the Cape York Peninsula, and in the north, the Gulf of Carpentaria. Another significant feature of the Australian topography is the Great Barrier Reef which is the largest coral reef in the world covering a distance of close to 2000km.
Use of Topography Maps
Maps for various purposes and by various stakeholders such as businesses and governments that use the map for urban planning, emergency management, establishing legal boundaries, mining. Land ownership, etc. it is also used for recreational purposes such as hiking, orienteering, and travelling.
Topographic maps and accurate and detailed geographical representation of features that are on the earth surface. These features usually include
Cultural – these area buildings, roads, urban development, airports, name of places, railways, administrative boundaries, geographic features, reserves, local and international borders.
Hydrography – these are streams, rivers, coastal flats, lakes, and swamps
Relief – cliffs and contours, mountains, valleys, and swamps
Vegetation – orchards and vineyards, cleared and wooded areas.
The map legend lists the key features and corresponding symbols on the map, and it is the means through which the map is interpreted.
Topography map usually shows a coordinate grid and geographic graticule that helps you determine the absolute and relative positions on the map.
Note that the map is just a three or two-dimensional representation of physical space at a point in time so the map can’t be entirely up to date as there would be changes to the cultural features and landscape over time. This means that every map is dated, but the level will depend on the location.
This is the scale of the map, and common map numbering systems include
1:1 Million Scale Numbering
General Reference Topographic Map Series 1:1 Million Scale
1:250 000 Scale Numbering
1:100 000 Scale Numbering
1:50 000 Scale Numbering
Maps are graphical representations of data collected over many years and from different sources which generally include state mapping agencies, local landholders and councils, field investigations, government agencies, commercial map makers, the general public, and satellite imagery. This data is held in several databases, and dedicated software is used to extract all the relevant data, manipulate it, and use it to produce the map. Looking at this, you will understand that mapping is a complex thing.
There over 130 Gigabytes of base topographic data available with Geoscience Australia as well about 1000 datasets which cover various features and themes, each having defined purpose.