在R中更改ggplot geom_polygon的颜色方案

Question

我正在使用地图库和ggplot的geom_polygon创建地图.我只想将默认的蓝色,红色,紫色配色方案更改为其他方式.我对ggplot非常新,所以如果我没有使用正确的数据类型,请原谅.以下是我使用的数据:

> head(m)
region      long      lat group order subregion Group.1 debt.to.income.ratio.mean    ratio total
17 alabama -87.46201 30.38968     1     1      <NA> alabama                   12.4059   20.51282    39
18 alabama -87.48493 30.37249     1     2      <NA> alabama                   12.4059 20.51282    39
19 alabama -87.52503 30.37249     1     3      <NA> alabama                   12.4059 20.51282    39
20 alabama -87.53076 30.33239     1     4      <NA> alabama                   12.4059 20.51282    39
21 alabama -87.57087 30.32665     1     5      <NA> alabama                   12.4059 20.51282    39
22 alabama -87.58806 30.32665     1     6      <NA> alabama                   12.4059 20.51282    39

> head(v)
          Group.1 debt.to.income.ratio.mean    ratio     region total
alabama       alabama                  12.40590 20.51282    alabama    39
alaska         alaska                  11.05333 33.33333     alaska     6
arizona       arizona                  11.62867 25.55556    arizona    90
arkansas     arkansas                  11.90300  5.00000   arkansas    20
california california                  11.00183 32.59587 california   678
colorado     colorado                  11.55424 30.43478   colorado    92

这是代码:

library(ggplot2)
library(maps)

states <- map_data("state")
m <- merge(states, v, by="region")
m <- m[order(m$order),]

p<-qplot(long, lat, data=m, group=group, fill=ratio, geom="polygon")

我已经尝试了下面和更多:

cols <- c("8" = "red","4" = "blue","6" = "darkgreen", "10" = "orange") 
p + scale_colour_manual(values = cols)
p + scale_colour_brewer(palette="Set1")
p + scale_color_manual(values=c("#CC6666", "#9999CC"))

Answer 1

问题是你使用的是色标,但是在图中使用了填充美学.您可以使用scale_fill_gradient()两种颜色和scale_fill_gradient2()三种颜色:

p + scale_fill_gradient(low = "pink", high = "green") #UGLY COLORS!!!

我scale_fill_brewer()抱怨在预期离散变量时提供连续变量的问题.一个简单的解决方法是创建离散箱,cut()然后将其用作填充美学:

m$breaks <- cut(m$ratio, 5) #Change to number of bins you want

p <- qplot(long, lat, data = m, group = group, fill = breaks, geom = "polygon")
p + scale_fill_brewer(palette = "Blues")