section_path: Types/Electronic
section_name: Electronic
paragraph_text: Electronic
  
  From the last quarter of the 20th century, the indispensable tool of the cartographer has been the computer. Much of cartography, especially at the data-gathering survey level, has been subsumed by geographic information systems (GIS). The functionality of maps has been greatly advanced by technology simplifying the superimposition of spatially located variables onto existing geographical maps. Having local information such as rainfall level, distribution of wildlife, or demographic data integrated within the map allows more efficient analysis and better decision making. In the pre-electronic age such superimposition of data led Dr. John Snow to identify the location of an outbreak of cholera. Today, it is used by agencies of humankind, as diverse as wildlife conservationists and militaries around the world.
  
  Even when GIS is not involved, most cartographers now use a variety of computer graphics programs to generate new maps.
  
  Interactive, computerized maps are commercially available, allowing users to zoom in or zoom out (respectively meaning to increase or decrease the scale), sometimes by replacing one map with another of different scale, centered where possible on the same point. In-car global navigation satellite systems are computerized maps with route planning and advice facilities that monitor the user's position with the help of satellites. From the computer scientist's point of view, zooming in entails one or a combination of:
  
  For example: