Introduction
Like General Reference Maps, Topographic Maps are a summary of the
landscape and show important physical (natural and man-made) features in
an area.
The primary difference is that they show elevation in detail.
Characteristics of topographic maps include:

they show elevation using contour lines. Put simply, a contour line is a
line which joins points of equal elevation above sea level

they have an emphasis on showing human settlement (roads, cities,
buildings etc), but may include some thematic information such as
vegetation or the boundaries of national parks

they are typically produced by government agencies – these are often
specialist mapping agencies and may have either a civilian or defence
purpose

they have well defined standards (called Specifications) which are
strictly adhered to – these vary between mapping agencies and the
scale of the map

they have very good location reference systems – including latitude
and longitude, but may also have grid lines

often have additional information such as an arrow pointing
to Magnetic North as well as True North.
Understanding Contours
This extract from a 1:50,000 scale map has been annotated in pink to highlight different
landscape features which can be identified using the contour lines. This map had a contour
interval of 20 metres.
Elevation is usually shown using contour lines. In simplistic terms a contour
line is a line which joins points of equal elevation. Where these lines are
above sea level they are simply called contour lines and where they are
below sea level they are called bathymetric contour lines.
Contour lines can tell an informed reader many things about the shape of
the land and its ruggedness. The closer contours are together the steeper
the land and the further they are away from each other the flatter the
land. On the Nullarbor Plain, for instance, very few contour lines would be
shown, but over the Snowy Mountains an enormous number of contour lines
would be shown.
A word of warning: topographic maps do not show every contour line, rather
they choose sample of the lines. For example every 20, 50, 200 metres –
depending on the scale of the map. This is called the contour interval of the
map. As a result of this selection process, the difference in density of the
contour lines is only indicating relative changes in the shape of the
landscape – on that map!
Read more about contours in A Map Users Guide to Reading Tactual and Low
Vision Maps.
Topographic Maps as a Summary of the Landscape – an
Example
This topographic map and photograph are of the same area – the Manly region within Sydney,
NSW. By comparing these two it is clear that the map is an excellent summary of the landscape
of the area. Note that the features which dominate the photograph also dominate the map. And,
because it is a topographic map, it also gives detailed information about the ‘bumpiness’ of the
land.
A 'Potted' Geography of Australia using Topographic Maps
Four maps have been selected across Australia to illustrate the vast range of
information which can be contained in a topographic map. These maps are
all part of a series of maps which cover the whole of Australia and they have
been produced using the same specification – i.e. any difference in
appearance of the map is the result of a difference in the landscape.
Larger versions of the maps are at the end of the doc for easier reading.
The first map is centred on the Pilbara region mining town of Paraburdoo. The area is lightly
settled and poorly vegetated. Because of this, the features shown on the map are less obscured
compared to other parts of Australia. In particular, the contour lines (shown in brown) are easily
seen – where they are close together the slope is greatest. Note the ranges (lines of hills)
crossing this map. Also note that the sparse settlement in this region is indicated by the small
number of roads and towns/buildings.
The second is centred in a broad–acre agricultural area (often called a wheat ⁄ sheep area) north
of Perth, Western Australia. Here the contour lines are far apart indicating gently sloping land
and, because there are no contours close together, it is clear that there are no ranges. A denser
settlement than our first example is indicated by the larger number of roads and the buildings
(the black squares) which are shown.
Our third map is in the wet tropical region around Darwin, Northern Territory. There are very few
contour lines, indicating that the land is very flat. Also, the much denser settlement is indicated
by the large number of buildings and the large city area (the area in pink – here the houses are
too close together to be shown separately – in mapping jargon this is called a built-up area).
A feature present here that has not been shown on the other two maps is vegetation. This
doesn't mean that there is no vegetation on the other maps, rather they have simply opted to not
show it or the vegetation is less dense. Forested land is shown in light green and mangrove
areas in dark green. Please note that this adds colour to the map, but can make the contour
lines hard to see.
Finally, the fourth map is over Sydney, NSW. With a population of about 4 million people, this is
Australia's largest city. The contours are close together, indicating hilly land. The city area
covers a large part of the map and there are a large number of buildings shown surrounding the
city. The road network is also very complex.