Basics of symbolization 141
symBol selectIon And desIgn
Symbolizing the content of a thematic map is a complex process. No simple step-by-
step guidelines or system can be provided, although there have been efforts at creating
design algorithms for some map elements. Symbolization cannot be executed inde-
pendently of other cartographic elements. There is no simple correspondence between
dimensions of geographic phenomena and dimensions of map symbols. Although
four categories of spatial phenomena exist, as we have seen, only three kinds of mark
can be used to represent those categories on a two-dimensional map. Any geographic
phenomenon can be interpreted in a variety of ways and can be represented with a
different symbol. Figure 7.9 shows the same data with a variety of different measure-
ments and symbolization.
The mapmaker must solve two problems in symbolization:
symbol selection
and symbol design.
Selection involves determining, according to the cartographer’s
concept of the phenomenon, the best general type of symbol to represent it.
Design
involves consideration of the characteristics of the phenomenon, the visual variables
of symbols, and the quality and level of measurement of the data to create the best
symbol design for a particular purpose. Bear in mind that there is no single best way
to represent the data.
