格式化ggplot2映射

Question

我试图用R中的ggplot2制作一张世界地图，我想显示巴西各州的人均国内生产总值。有两个问题：

1. 在这个国家的中心有两个标签不容易读懂的信息。他们是overlapping.Reducing，数字还没有解决。
2. 我想要改变颜色，不知道如何访问它。我想用颜色变得容易注意到GDP的差异。

我的数据是：coFit6AovfcEFkbHBjZEJaQ1E/edit

这是我的代码：

library(maptools)
gpclibPermit()
library(ggplot2)
library(rgdal)
library(rgeos)
library(ggmap)


# read administrative boundaries (change folder appropriately)
brMap <- readShapePoly("BRASIL.shp")
brMap

# read downloaded data (change folder appropriately)
brRen <- read.csv("Renda.csv", sep = ";", quote = "\"", dec=".", stringsAsFactors = FALSE)
brRen$rendapc <- as.numeric(as.character(brRen$rendapc)) # format as numeric

#convert shp to UTF8
library(descr)
brMap$ESTADO<-toUTF8(brMap$ESTADO, "IBM850")

# convert shp data to data frame for ggplot
as.data.frame(brMap) # para definir a region
brMap = gBuffer(brMap, width=0, byid=TRUE) #correct problem with Polygons - TopologyException
brMapDf <- fortify(brMap, region="UF")
brMapDf


# merge map and data
brRenMapDf <- merge(brMapDf, brRen, by.x="id", by.y="Iden")
brRenMapDf <- brRenMapDf[order(brRenMapDf$order),]

# limit data to main Europe
brazil.limits <- geocode(c("Monte Caburaí", "Barra do Chuí", "Serra do Divisor", "Ilhas Martin Vaz"))
brRenMapDf <- subset(brRenMapDf, long > min(brazil.limits$lon) & long < max(brazil.limits$lon) & lat > min(brazil.limits$lat) & lat < max(brazil.limits$lat))

# ggplot mapping
# data layer
m0 <- ggplot(data=brRenMapDf)
# empty map (only borders)
m1 <- m0 + geom_path(aes(x=long, y=lat, group=group), color='gray') + coord_equal()
m1

# fill with education expenditure data
m2 <- m1 + geom_polygon(aes(x=long, y=lat, group=group, fill=rendapc))
m2


# inverse order (to have visible borders)
m0 <- ggplot(data=brRenMapDf)
m1 <- m0 + geom_polygon(aes(x=long, y=lat, group=group, fill=rendapc)) + coord_equal()
m2 <- m1 + geom_path(aes(x=long, y=lat, group=group), color='black')
m2


# over a GoogleMap (not working if not correctly projected)
map <- get_map(location = 'Brazil', zoom=4)
m0 <- ggmap(map)
m1 <- m0 + geom_polygon(aes(x=long, y=lat, group=group, fill=rendapc), data=brRenMapDf, alpha=.9)
m2 <- m1 + geom_path(aes(x=long, y=lat, group=group), data=brRenMapDf, color='black')
m2


# add text
library(doBy)
txtVal <- summaryBy(long + lat + rendapc ~ id, data=brRenMapDf, FUN=mean, keep.names=T)
m3 <- m2 + geom_text(aes(x=long, y=lat, label=rendapc), data=txtVal, col="yellow", hjust=0.5, vjust=0.5, cex=3)
m3

我想提高我的成绩：

​

​

Answer 1

在改变色标方面，ggplot2有统一的处理方法。您要寻找的函数始终具有scale_{which_scale}_{scale_type}格式，其中which_scale是一种美学(您在aes()中使用的东西，例如fill或size)，scale_type可以是连续的或离散的，等等。如果您想要调整fill比例，需要的是scale_fill_continuous、scale_fill_gradient或scale_fill_gradient2。请查看这些功能的文档。

代码示例：

m2 <- m1 + geom_polygon(aes(x=long, y=lat, group=group, fill=rendapc))
m2 + scale_fill_gradient(low = "blue", high = "red")