Comparing Equal Interval and Quantile Classifications

What is different about these two maps? The data are the same, though the interpretation of each map (and thus of the data) might be quite different. The only difference between the maps is the methods used to classify the data: The top map uses the Equal Interval method, and leaves the impression that the percent of population living on active farms is about the same from the northeast corner of the region through the entire southern one-third.

The bottom map shows this same data classified according to a Quantile classification method, and this map shows what appears to be a large percentage of active farmers throughout the north.

The classification method you choose can have a large bearing on the final impression produced by the map.

Take a look at other classification methods.