What is a map?
Introduction
One of the most important tools of a geographer is a map. Geographers, however, are not the only people who use maps. People encounter maps in everyday life. Weather maps are featured on the news. People even refer to simple maps when trying to navigate around public places, such as libraries and train stations. This chapter outlines what constitutes a map and the problems which arise when attempting to construct one.
What is a map?
A map is essentially a simplified, diagrammatic representation of a three-dimensional space. While a map can feature the location of astronomical objects when viewed from Earth, in the field of geography, a map concerns the Earth's surface as if seen from directly above. Maps are usually two dimensional, although modern technology has provided for the development of three-dimensional, computer-generated maps. Maps can also be represented on the surface of a sphere. This is called a globe.
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The scientific and artistic technique of organising spatial information on a map or chart is called cartography. A person who creates these maps is called a cartographer.
Maps can range from being highly detailed, outlining cultural and physical features, to being simple sketches which mark paths on a bushwalking map. Whether a complex or simple map, most maps share seven essential features.
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title: to ensure that the person using it knows what the map is about and where it is representing
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border: to prevent any misunderstandings about where the map ends
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source: to show where the information was obtained from
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latitude and longitude: to be able to identify specific locations on the map
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legend (key): to explain the meanings of symbols used on the map
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scale: to show how the dimensions of features on the map correspond with the dimensions of the features they represent in the real world
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direction (orientation): to explain where something is in relation to something else
The last four features will be addressed more comprehensively in following chapters.
Types of maps
Indigenous Australians are responsible for some of the earliest maps in Australia. Since many Indigenous maps are believed to have been drawn in the soil or sand, there are very few extant (still existing) examples. There are some Indigenous maps, however, which were painted on bark, that have managed to survive. These surviving maps provide an insight into the ancient Indigenous culture, owing to them being of places associated with the Dreaming.
Even though these traditional Indigenous maps appear to be very different from modern day maps, they share a number of similarities. Like common modern maps, Indigenous bark maps often include cultural features, such as camp sites and land borders, as well as physical landforms, such as water holes. Indigenous artwork, including maps, also uses certain symbols to represent common features, which is a technique shared by modern cartographers.
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There are many different types of modern maps, all of which are used for a wide variety of purposes. The most common maps are political maps and physical maps. Political maps outline cultural features including country or state boundaries and capital cities. Physical maps indicate major physical (natural) features including mountain ranges, deserts, lakes and rivers. The information on political and physical maps is sometimes combined to form reference maps.
Certain professions often rely on particular maps. Demographers (people who study the statistics of the human population) use population maps, meteorologists (specialists who study weather and climate) rely on synoptic charts, ecologists (scientists who study the relationship between organisms and their environment) use vegetation maps, and couriers and taxi-drivers are likely to rely on street directories.
Among the most widely used maps are topographic maps. Topographic maps precisely show the surface features of a region, using contour lines which join places of equal altitude. They were originally used by the military but have also become useful tools for geologists, surveyors and real estate developers.
The most diverse type of maps would be thematic maps. Thematic maps show the spatial distribution of a theme (feature or phenomena). Themes can include employment, historical sites, world alliances, football World Cup host nations and major earthquakes.
Map projection
While modern cartographers are able to access advanced satellite technology to create maps, cartography is not a simple undertaking. The most difficult task faced by cartographers is how to represent a three-dimensional curved surface (the Earth) on a flat plane (paper) without losing any accuracy. Since the Earth is spherical in shape, it cannot be unrolled to lie exactly flat without making any alterations.
Cartographers have devised a number of different methods (called map projections) to show the Earth on a flat surface. There are four types of map projections: azimuthal or planar, conic, cylindrical and interrupted. All map projections, however, make compromises on the shape, size or direction of the Earth's surface.
Since this issue of accuracy cannot be escaped, cartographers usually choose to preserve different properties according to the purpose of the map. The Mercator projection, for example, is often used for nautical navigation maps. This projection was selected because even though the areas and shapes of the continents are not precise, it manages to maintain true compass direction. In comparison, world maps are often created using the Mollweide projection, and its hybrid projections (including the Robinson projection), which accurately represent areas, but distort distances and compass directions.
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