scale_fill_brewer自定义标签与ggplot2

Question

我做了以下情节：

我使用了这段代码：

library(XML)
library(ggplot2)
library(scales)
library(plyr)
library(maps)

unemp <-
  readHTMLTable('http://www.bls.gov/web/laus/laumstrk.htm',
                colClasses = c('character', 'character', 'numeric'))[[2]]

names(unemp) <- c('rank', 'region', 'rate')
unemp$region <- tolower(unemp$region)

us_state_map <- map_data('state')
map_data <- merge(unemp, us_state_map, by = 'region')

map_data <- arrange(map_data, order)

states <- data.frame(state.center, state.abb)

p1 <- ggplot(data = map_data, aes(x = long, y = lat, group = group))
p1 <- p1 + geom_polygon(aes(fill = cut_number(rate, 5)))
p1 <- p1 + geom_path(colour = 'gray', linestyle = 2)
p1 <- p1 + scale_fill_brewer('Unemployment Rate (Jan 2011)', palette  = 'Set1')
p1 <- p1 + coord_map()
p1 <- p1 + geom_text(data = states, aes(x = x, y = y, label = state.abb, group = NULL), size = 2)
p1 <- p1 + theme_bw()
p1

我想在一些操作之后显示scale_fill_brewer自定义标签，例如将每个标签乘以100或1000之后。

Answer 1

虽然ggplot助手函数很方便，但我更喜欢在绘图成语之外进行数据争论。这使用cut为自定义标签添加1％的中断，并使用正确的美国投影，并且具有更适合此数据的顺序色标，并且（最终）删除了大量的图表垃圾：

library(XML)
library(ggplot2)
library(scales)
library(plyr)
library(maps)
library(ggthemes)

unemp <-
  readHTMLTable('http://www.bls.gov/web/laus/laumstrk.htm',
                colClasses = c('character', 'character', 'numeric'))[[2]]

names(unemp) <- c('rank', 'region', 'rate')
unemp$region <- tolower(unemp$region)

# gain granular control of the breaks outside of ggplot
unemp$brk <- cut(unemp$rate, 0:9, labels=c("0%", sprintf("≥%d%%", 1:8)))

head(unemp)
##   rank       region rate brk
## 1    1     nebraska  2.6 ≥2%
## 2    2 north dakota  3.1 ≥3%
## 3    3         utah  3.5 ≥3%
## 4    4      vermont  3.6 ≥3%
## 5    5         iowa  3.8 ≥3%
## 6    5    minnesota  3.8 ≥3%

us_state_map <- map_data('state')
map_data <- merge(unemp, us_state_map, by = 'region')

map_data <- arrange(map_data, order)

states <- data.frame(state.center, state.abb)

p1 <- ggplot(data = map_data, aes(x = long, y = lat, group = group))
p1 <- p1 + geom_polygon(aes(fill = brk))
p1 <- p1 + geom_path(colour = 'black', linestyle = 2, size=0.25)
# use a sequential color scale since that's appropriate for the data
p1 <- p1 + scale_fill_brewer('Unemployment Rate (Jan 2011)', palette  = 'YlGnBu')
# use a proper projection for the U.S.
p1 <- p1 + coord_map("albers", lat0=39, lat1=45)
p1 <- p1 + geom_text(data = states, aes(x = x, y = y, label = state.abb, group = NULL), size = 2)
p1 <- p1 + labs(x=NULL, y=NULL)
p1 <- p1 + theme_map()
p1 <- p1 + theme(legend.position="right")
p1

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