Part 2: Representing geographic information in a computer

Question 7: What are the essential elements of geographic information?

Geographic information is simply information that can be located. The most obvious source of geographic information is maps, in which information about the world around us is plotted within a structured framework (a coordinate system) that allows us to find its location. However, maps are not simple representations of geographic information and are themselves produced by combining the three essential components of geographic information:

The location of the geographic information – maps use a coordinate system to allow locations to be read
The shape (geometry) of the geographic information – the shape of the features and themes are drawn onto the map
The description of the geographic information – a legend provides descriptions of the shapes drawn on the map

Any system that is capable of working with geographic information must, therefore, also be able to:

Create a space in the which locations of features can be plotted
Plot and store information that describes the shapes of the features in the location space
Store information that describes what the shapes represent