Creating bar chart (for sorting purposes) and, finally, a choropleth map

Choropleth Map

data <- read.csv("county-data.csv")

#adds a county column by splitting in front of the parenthesis
data$county <- sapply(strsplit(as.character(data$ACCOMACK.VA.), split="\\("), function(x) { x[1] })

#adds a state column by splitting after the parenthesis
data$state <- sapply(strsplit(as.character(data$ACCOMACK.VA.), split="\\("), function(x) { x[2] })

#resplit the state data to get rid of the parenthesis sign at the end
data$state <- sapply(strsplit(as.character(data$state), split="\\)"), function(x) { x[1] })

#getting data for each state
get_state_data <- function(mystate) {this_state_data <- subset(data, state == mystate) }

#turn data$guns into a number
data$guns <- as.numeric(gsub("\\,","", data$X1))

#create a new dataframe that aggregates the guns for each state
guns_state <- aggregate(data$guns, list(data$state), sum)

#sort it by the number of guns so it makes a pretty graph
guns_state2 <- guns_state[order(guns_state$x, decreasing = TRUE), ]

#plot it like a boss
barcolors <- ifelse(guns_state2$Group.1 == "IL", "red", "lightgray")
barplot(guns_state2$x, ylab="Number of Guns", xlab="States", col=barcolors, border=F)

#add some labels
text(guns_state2$x + 400, guns_state2$Group.1, adj=c(.5, NA), labels=guns_state2$Group.1, col="blue", cex=.7)

install.packages("maptools")

library(maptools)

shapes <- readShapePoly("nytlayout_state/nytlayout_state.shp")

install.packages("RColorBrewer")

library(RColorBrewer)

map_data <- data.frame(shapes)

#getting rid of Guam and Hawaii
guns_state5 <- guns_state2[-53,]
guns_state5 <- guns_state3[-49,]

#match the data (make sure you put the map data first--but I don't know why)
match_order <- match(map_data$STATE_ABBR, guns_state5$Group.1)
map_data$guns <- guns_state3$x[match_order]

#plotting
map_breaks <- c(0, 50, 100, 250, 500, 750, 1000, 2500, 5000, 25000)
buckets <- cut(map_data$guns, breaks=map_breaks)
numeric_buckets <- as.numeric(buckets)
colors <- brewer.pal(9, "YlOrRd")
plot(shapes, col=colors[numeric_buckets])