Thursday, September 11, 2008

Dot Distribution map

Dot Distribution maps portray quantitative data as a dot, which represents a number of any particular phenomenon in question found within the boundary of a certain geographic area. The pattern of distributed dots reflects the general locations where the phenomenon most likely occurs. The pattern and number of dots within a geographic area reveal the density of the phenomenon in question. There are 2 types of dot-distribution maps: the first type is a traditional dot map showing the distribution of a phenomenon; and the second type is an increase/decrease dot map. This ype of dot-distribution map shows increasing (positive) and decreasing (negative) values of a phenomenon.
Dot distribution maps are especially helpful in showing population, portraying quantitative populations as dots. Say I wanted to illustrate population of the United States, with each dot representing a defined number of people. Below is a representation of what this would look like:

The white areas are the most populated areas of this nation, according to the 2000 census. each white dot represents a specific number of people, so those areas where the white dots are more concentrated are more densely populated.

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