This digital elevation model shows Mount Etna, Sicily, in three dimensions. It was created from visible light and infrared images...Read More >>This digital elevation model shows Mount Etna, Sicily, in three dimensions. It was created from visible light and infrared images taken by the ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) sensor on board the Terra Earth observation satellite. Digital elevation models can be used to study the terrain or to create detailed topographical maps. There have always been two key tasks in map-making (also called cartography). The first task is to collect information about the Earth. The second task is to combine, select and display that information on a map in a useful and attractive way. During the late 20th century, new ways of collecting information changed cartography for ever. These methods make use of new technology, such as satellites, lasers and radar. Today, the information collected is usually called “data” as it is stored digitally on a computer. The development of new computer systems—called geographic information systems (GIS)—also changed the way data is worked with and displayed. Cartographers are highly skilled, but today anyone can have a go at being a map-maker, using mapping software, websites and apps that let us download basic maps, alter their scale and decide which features to display.
Using this GIS, called GeaBios, the user is selecting information for Papeete in French Polynesia. The user can then select how...Read More >>Using this GIS, called GeaBios, the user is selecting information for Papeete in French Polynesia. The user can then select how the information will be displayed.
Geographic information systems
Geographic information systems (GIS) are computer systems that store geographical information from a range of sources, from satellite images to geophysical surveys. A GIS can combine, select and display all this information for any given place. GIS are used by cartographers to create maps with an endless variety of scales, themes and styles.
Simplified GIS can be used on navigation websites and apps—for example, the user can decide which features to show on their personalized map, from restaurants to petrol stations.
The first satellite photographs of Earth were taken by the US Explorer 6 satellite on 14th August 1959.
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