Other Software : Geographical Information Systems (GIS)

A Geographical Information System (GIS) presents stored data graphically on a map. The most common use of a geographical information system is as part of an in-car satellite navigation (SatNav) system, used to give a driver directions to get to his destination.

Satellite Navigation (SatNav)

A satellite navigation system consists of a receiver, a computer, a CD-ROM or DVD-ROM drive, an LCD monitor and a keyboard or remote control.

The receiver receives signals from a network of satellites called Global Positioning Satellites (GPS). From these the computer system can work out the location of the car. Maps are stored on a CD or DVD and based on the position of the car the computer can load the correct map and display it on the monitor with the car's position indicated.

Before setting out on a journey the driver can enter the name or postcode of the place that he is travelling to. The computer can locate the destination on the map and work out the best route for the driver to take. As the journey progresses the monitor will be used to indicate when the driver should turn onto another road. Directions may also be announced through speakers using speech synthesis so that the driver does not have to take his eyes off the road.

A satellite navigation system may also be linked to a traffic information system which can receive information about traffic jams and roadworks by radio. If a road involved in a journey is busy the computer system will be able to automatically change the recommended route to minimise the delay.

Other Geographical Information Systems

Geographical information systems can also be used to help analyse data by plotting it on a map. For example :

• The Police could plot data about where crimes have been committed on a map to identify the areas that suffer from most crime so that they can deploy more officers in these areas.
• An insurance company could plot data about claims that homeowners have made on a map to help them identify what premiums to charge for house insurance in different areas.
• A political party could plot data about people who have promised to support it on a map to identify areas in which they should campaign to increase their support.

All of these tasks are made easier by seeing the data viewed on a map rather than as a list in a table. Most geographical information systems will be able to display a map at different levels of magnification so that as much or as litte detail as is required can be seen.

GCSE ICT Companion 04 - (C) P Meakin 2004