If the objective of the map is to represent the high and low extremes, then the bottom figure does a much better job than the middle one, both in terms of how the data are divided and how they are symbolized with colors. The bottom figure divides the data into standard deviation units such that the blue and red values are the focus of attention. In the middle figure, the visual message is almost lost in a combination of a poor choice of colors and shading symbols and a confusing division of the data into classes. The visual messages conveyed by the maps are different, yet the underlying geographies and statistics are identical. This example emphasizes the importance of the map as a medium for the interpretation of information.
Subjective choices relating to both the art and science content of the map are critical.
Figure 1.6 also reminds us that it is just as easy to lie with maps as it is to lie with statistics. It is more likely that the compiler of the map misleads readers by choosing inappropriate designs rather than by intentionally falsifying information. This may happen on several levels, the most basic being that the author of the map created it to achieve an objective different from that experienced by the readers. Next are issues related to data manipulation and cartographic art. Ultimately, the possibilities for misrepresentation and misinterpretation are virtually infinite.