在ggplot2中为具有不同颜色深度的地图着色

编程问答 2022-05-23

问题描述

我正在尝试用特定颜色“#2D3E50”绘制巴西地图。但是，在地图上使用此颜色从最小区域（浅色）到最大区域（深色）着色是行不通的。请参阅下面我尝试为不同比例插入的所选颜色。

library(geobr)
library(ggplot2)
library(cowplot)
library(RColorBrewer)
library(dplyr)

dados <- structure(
  list(X = 1:27,uf = c("Acre","Alagoas","Amapá","Amazônas","Bahia","Ceará","distrito Federal","Espírito Santo","Goiás","Maranhão","Mato Grosso do Sul","Mato Grosso","Minas Gerais","Paraíba","Paraná","Pará","Pernambuco","Piauí","Rio de Janeiro","Rio Grande do norte","Rio Grande do Sul","Rondônia","Roraima","Santa Catarina","São Paulo","Sergipe","Tocantins"),AreaTotal = c(0,0.01,0.07,0.6,0.23,0.14,0.24,1.14,1.96,1.01,0.21,0.03,0.83,0.64,1.4,0.15)),class = "data.frame",row.names = c(NA,-27L))
states <- read_state(code_state = "all",year = 2019)
states$name_state <- tolower(states$name_state)
dados$uf <- tolower(dados$uf)

states <- dplyr::left_join(states,dados,by = c("name_state" = "uf")); states

no_axis <- theme(axis.title=element_blank(),axis.text=element_blank(),axis.ticks=element_blank())

ggplot() + 
  geom_sf(data=states,aes(fill = AreaTotal),color=NA,size=.15) +
  no_axis + labs(size=8) + scale_fill_distiller(palette = "2D3E50",name="Áreas",limits = c(0,2))

Warning message:
In pal_name(palette,type) : UnkNown palette 2D3E50

看到它会自动填充绿色，而且颜色是相反的，因为较暗的区域显示较低的区域。

解决方法

RColorBrewer 包不包含名为#2D3E50 的调色板。因此，用它们各自的深浅来阐述一系列颜色就足够了，即低值和高值的颜色，它们是：low = "white",high = "#2D3E50"。

ggplot() + 
  geom_sf(data = states,aes(fill = AreaTotal)) +
  no_axis + 
  labs(size = 8) + 
  scale_fill_gradient(low = "white",high = "#2D3E50",name = "Áreas",limits = c(0,2))

geostatisticsggplot2plotrrstatistics