External representations

External representations consist of

• (1) the represented world - the content of a representation (e.g., content of a weather map would be temperatures around the country)
• (2) the representing world - the format of the representation (e.g., temperatures can be represented by different colors in pictorial form, or by a table)
• (3) what aspects of the represented world are being represented (e.g., weather map may have states delineated, but not cities)
• (4) what aspects of the representing world are doing the modelling (e.g. colors map to temperatures)
• (5) the correspondence between the two worlds (how the content is mapped to the format)

(Palmer, 1977).