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How GPS works

A GPS device receives signals from more than three satellites in space. The different times it takes for the satellite signals to reach the GPS receiver will help the receiver tell you your location. Most of these GPS receivers can identify the location within three metres. They could easily be more accurate, but the USA military don’t want other people to have any greater accuracy.  

There are two types of GPS devices that can be used for this project. 

  • A bushwalking GPS can record different locations. These locations that are recorded are called waypoints. There will be a maximum number of waypoints that a GPS receiver can record. You will need to read the instruction booklet and train yourself to use the device. These GPS machines usually come with software. It should be possible to transfer your waypoints to a map on the computer. You can organise the waypoints as a touring map which can be uploaded to the GPS and the handset will guide you to each of your locations at future photographic surveys. There is a lot to learn. A number of software programs will take the data collected on the GPS (every time a waypoint was recorded) and transfer it as you download your photos onto a computer. 
  • A much more expensive option is to have a dedicated GPS device attached to the camera. Probably by 2011 it will be possible to buy small inexpensive cameras with GPS. With these cameras when the GPS is attached and activated, the camera records the location of every photo. (I have not used such a device.) I doubt if it has the capacity to record the direction as the GPS technology on its own can only pinpoint direction while the receiver is moving. Using this method is less helpful at mapping out your photo directions. 

To my knowledge car GPS devices do not provide coordinates. 

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