Geography Reference
In-Depth Information
Figure 3.3: Classifying countries by population
the world. Well, we are in luck. Our world_borders layer just happens
to have an attribute named POP_CNTRY that contains the population
of each country. To make Harrison happy, we can use what's termed a
class break method to symbolize the data. The Style Editor has a Theme
panel to classify the layer based on an attribute. In Figure 3.3 , we can
see the settings we can use to classify the world boundaries based on
population. We set up ten equal interval classes based on the range of
population values. The less populated countries will be colored in light
blues or greens, while the countries with the largest populations will be
rendered in a shade of purple. We could also do a quantile classification,
putting roughly the same number of values in each class. But for our
purpose, the equal intervals work just fine.
 
 
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