Two general characteristics of maps emerge from such seemingly whimsical examples as Jorge Luis Borges's cartographic empire (see ITEM 1.2) and the Bellman's blank chart (see ITEM 1.3). Firstly, maps are selective: they do not, and cannot, display all there is to know about any given piece of the environment. Secondly, if they are to be maps at all they must directly represent at least some aspects of the landscape.
The Bellman's blank Ocean Chart from Lewis Carroll's *The Hunting of the Snark*.
The Bellman himself they all praised to the Skies–
Such a carriage, such ease and such grace!
Such solemnity too! One could see he was wise,
The moment one looked in his face!
He had brought a large map representing the sea,
Without the least vestige of land:
And the crew were much pleased when they found it to be
A map they could all understand.
'What's the good of Mercator's North Poles and Equators,
Tropics, Zones and Meridian lines?'
So the Bellman would cry; and the crew would reply,
'They are merely conventional signs!
'Other maps are such shapes, with their islands and capes!
But we've got our brave captain to thank'
(So the crew would protest) 'that he's brought us the best–
A perfect and absolute blank!
We may divide the types of representation in maps into two different types: iconic representation (which attempts to directly portray certain visual aspects of the piece of territory in question) and symbolic representation (which utilises purely conventional signs and symbols, like letters, numbers or graphic devices). For example, look at ITEM 6.1 and try to distinguish those elements of the map which are representational (iconic) from those which are entirely reliant on arbitrary convention (symbolic).
J. B. Harley and David Woodward have recently proposed an all-embracing definition of maps: 'Maps are graphic representations that facilitate a spatial understanding of things, concepts, conditions, processes, or events in the human world' (J. B. Harley & D. Woodward (eds), The history of cartography, vol. 1, 1987, p. xvi). For our purposes we can take a working definition of a map as a graphic representation of the milieu, containing both pictorial (or iconic) and non-pictorial elements. Such representations may include anything from a few simple lines to highly complex and detailed diagrams.