Maps are a graphic representation of the earth, showing the spatial relationship of the earth’s featureswhether cultural or physical. Central to this representation is reducing the earth’s features of interestto a manageable size (i.e., map scale) and its transformation into a functional two-dimensional form(i.e., map projection). As all maps are visual representations of selected phenomena, a cartographermust consider the key concepts that make a map a map: it is a scaled, selective, symbolized, andabstracted graphical representation of the phenomenon [4] [5].
Scaled: Scaled refers to the fact that almost all maps are more useful when they are reproduced at asmaller scale than the actual phenomenon being mapped. For example, a road map of Idaho thatwhen unfolded is the actual size of Idaho, is not very useful to us, so instead, we reduce the size ofthe spatial phenomenon being represented onto a more reasonably sized piece of paper [5].
Selective: Selective means that maps should only include items that are directly related to themessage of the map. For instance, a map designated to show where all the hospitals are locatedwithin a city should not include the location of every manhole cover in the city. The reason being, thelocation of the manhole covers is irrelevant to the locations of the hospitals, and therefore it would bea meaningless feature on the map and likely detrimental to achieving the map’s purpose [5].
Symbolized: Symbolized, refers to the idea of extracting the item being mapped by using arepresentative symbol. Examples of representative symbols would be a star with a circle around itthat represents a state capital, or a symbol of the front of a bus that represents a bus stop [5].Abstracted: Decisions about how to classify, simplify, or exaggerate features and how to symbolizeobjects of interest simultaneously fall under the realms of art and science. Moving from the real worldto the world of maps is map abstraction. This process involves making choices about how torepresent features. Regarding geographic information systems (GIS), we must be explicit, consistent,and precise in defining and describing geographical features of interest [4]</p
