Data classification methods: percent black population in Escambia County, Florida

This week we used Census 2000 population data for Escambia County, Florida, and looked at the percent black population in each census tract, using four different data classification methods.

I think quantiles is the most appropriate method (see the larger map) because it shows in greatest detail the low end of the scale, where 40% of the population is classified in two low-percentage categories. Equal interval does not represent the data well because it ignores its uneven distribution and merely divides the number of census tracts by five and organizes the categories accordingly. I think standard deviation doesn't represent the data well either in this case. It is better at showing the extreme outliers, which in this case are only the small number of heavily black census tracts, than it is at expressing the percent black distribution across the county. Natural breaks has a lot of similarities to the quantiles display, but it displays in greater detail the high end of the scale, which has only a small proportion of the census tracts, at the expense of showing in detail the low end of the scale, which contains a much greater proportion of the census tracts.