The county data set offers many numerical variables that we could plot using dot plots, scatterplots, or box plots, but these miss the true nature of the data. Rather, when we encounter geographic data, we should map it using an intensity map, where colours are used to show higher and lower values of a variable. Figures LABEL:countyIntensityMaps1 and LABEL:countyIntensityMaps2 shows intensity maps for federal spending per capita (fed_ spend), poverty rate in percent (poverty), homeownership rate in percent (homeownership), and median household income (med_ income). The colour key indicates which colours correspond to which values. Note that the intensity maps are not generally very helpful for getting precise values in any given county, but they are very helpful for seeing geographic trends and generating interesting research questions.
R>val=county[,5]; val[val > 18]=18
R>countyMap(val, county[,11], "ye", gtlt=">")
R>val=county[,6]; val[val > 25]=25
R>countyMap(val, county[,11], "red", gtlt=">")
R>val=county[,7]; val[val < 55]=55
R>countyMap(val, county[,11], "bg", gtlt="<")
R>val=county[,10/1000; val[val > 60]=60
R>countyMap(val, county[,11], "green", gtlt=">")
What interesting features are evident in the fed_ spend and poverty intensity maps?
Answer. The federal spending intensity map shows substantial spending in the Dakotas and along the central-to-western part of the Canadian border, which may be related to the oil boom in this region. There are several other patches of federal spending, such as a vertical strip in eastern Utah and Arizona and the area where Colorado, Nebraska, and Kansas meet. There are also seemingly random counties with very high federal spending relative to their neighbours. If we did not cap the federal spending range at $18 per capita, we would actually find that some counties have extremely high federal spending while there is almost no federal spending in the neighbouring counties. These high-spending counties might contain military bases, companies with large government contracts, or other government facilities with many employees.
Poverty rates are evidently higher in a few locations. Notably, the deep south shows higher poverty rates, as does the southwest border of Texas. The vertical strip of eastern Utah and Arizona, noted above for its higher federal spending, also appears to have higher rates of poverty (though generally little correspondence is seen between the two variables). High poverty rates are evident in the Mississippi flood plains a little north of New Orleans and also in a large section of Kentucky and West Virginia.
What interesting features are evident in the med_ income intensity map?
Answer. Note: answers will vary. There is a very strong correspondence between high earning and metropolitan areas. You might look for large cities you are familiar with and try to spot them on the map as dark spots.