如何在ggplot中为地图中的多个图层自定义图例？

编程问答 2022-06-10

问题描述

我正在尝试修复字幕，但是创建字幕时遇到了麻烦。我想要为类（填充），形状限制（颜色），点（颜色）和网格（填充= NA）添加标题。我将它们全部放在aes ()中，但没有得到预期的结果。有谁能够帮助我？谢谢！

library(geobr)
library(sf)
library(ggplot2)
library(ggspatial)

#Directory

getwd()

#Download spatial data ------------------------------------------------

download.file(url = "http://geo.fbds.org.br/SP/RIO_CLARO/USO/SP_3543907_USO.dbf",destfile = "SP_3543907_USO.dbf",mode = "wb")
download.file(url = "http://geo.fbds.org.br/SP/RIO_CLARO/USO/SP_3543907_USO.prj",destfile = "SP_3543907_USO.prj",mode = "wb")
download.file(url = "http://geo.fbds.org.br/SP/RIO_CLARO/USO/SP_3543907_USO.shp",destfile = "SP_3543907_USO.shp",mode = "wb")
download.file(url = "http://geo.fbds.org.br/SP/RIO_CLARO/USO/SP_3543907_USO.shx",destfile = "SP_3543907_USO.shx",mode = "wb")

#Import spatial data --------------------------------------------------

uso <- sf::st_read("SP_3543907_USO.shp")
uso
plot(uso$geometry)

#Area limit

rio_claro_limit <- geobr::read_municipality(code_muni = 3543907,year = 2015)
rio_claro_limit
plot(rio_claro_limit$geom)

#Random sample points

set.seed(123)
pts <- st_sample(uso,size = 20,type="random") %>% st_sf

#Grid 50km x 50km

grid_50 <- st_make_grid(uso,cellsize = c(5000,5000)) %>% 
  st_sf(grid_id = 1:length(.))

#Labels grid

grid_lab <- st_centroid(grid_50) %>% cbind(st_coordinates(.))

#Points in grid

pts %>% st_join(grid_50,join = st_intersects) %>% as.data.frame


#Map --------------------------------------------------------------------

ggplot() +
  geom_sf(data = uso,aes(fill = CLASSE_USO,color = NA)) +
  geom_sf(data = rio_claro_limit,aes(color = 'black',fill = NA)) +
  geom_sf(data = pts,aes(color = 'red'),size = 1.7) + 
  geom_sf(data = grid_50,aes(fill=NA),lwd = 0.3) +
  geom_text(data = grid_lab,aes(x = X,y = Y,label = grid_id),size = 2) +
  xlab("")+
  ylab("")+
  scale_fill_manual(name="Classes de Uso",values = c("blue","orange","gray30","forestgreen","green",NA))+
  scale_color_identity(guide = "legend")

enter image description here

解决方法

您的期望结果可以这样实现：

  1. 我将所有fill=NA和color=NA从aes()语句中移出了。与往常一样，如果您要固定颜色，在特定值上填充或更一般地填充任何aes，则最好将其放在aes（）之外，除非您希望它出现在图例中。

  2. 将所谓的key_glyph设置为"point"，即图例中在图例中绘制的图标。

由于这些步骤还消除了填充键周围的黑色边框，因此我添加了guides层以将其恢复。我个人会删除黑色边框，但是，这是您的情节。 （：

library(geobr)
library(sf)
library(ggplot2)
library(ggspatial)

ggplot() +
  geom_sf(data = uso,aes(fill = CLASSE_USO),color = NA) +
  geom_sf(data = rio_claro_limit,aes(color = 'black'),fill = NA,key_glyph = "point") +
  geom_sf(data = pts,aes(color = 'red'),size = 1.7,key_glyph = "point") + 
  geom_sf(data = grid_50,lwd = 0.3) +
  geom_text(data = grid_lab,aes(x = X,y = Y,label = grid_id),size = 2) +
  xlab("")+
  ylab("")+
  scale_fill_manual(name="Classes de Uso",values = c("blue","orange","gray30","forestgreen","green",NA)) +
  guides(fill = guide_legend(override.aes = list(color = "black"))) +
  scale_color_identity(guide = "legend")

ggplot2ggspatiallegendrrsf