用ggplot2绘制Shapefile

用户143853

我想在一个绘图中创建包含九张（在此示例中只有三张）地图的构面。当我subset从原始的时候，我设法绘制了理想的一张地图shapefile。但是，当我尝试一次绘制所有图时，这是不可能的。

1, 2, 3, 4, 5即使某些地图仅具有从1到的值，该图也需要具有相同的图例（离散值作为值）4。

此外，当其中一个多边形缺少数据时，应将其绘制为带有图例的灰色NA value。

下面代码的输出示例在底部。此处提供示例数据。

path <- '~path'
muniCluster <- rgdal::readOGR(dsn=path, layer="data")

class(muniCluster)
[1] "SpatialPolygonsDataFrame"
attr(,"package")
[1] "sp"


ilum <- subset(muniCluster, CLUSTER == "CLUS_ILUM")
ilum$VALUES <- as.integer(ilum$VALUES)

ilum_df <- fortify(ilum)
ilum_tidy <- tidy(ilum)

class(ilum_df)
class(ilum_tidy)

# Recategorizes data as required for plotting
ilum$id <- row.names(ilum)
ilum_tidy <- left_join(ilum_tidy, ilum@data)
ilum_tidy$VALUES <- as.factor(ilum_tidy$VALUES)

ilum_map_v2 <- ggplot(ilum_tidy, aes(x = long, y = lat, group = group, fill = VALUES)) +
     geom_polygon(color = "black", size = 0.1) +
     labs(title = "Light cluster") +
     scale_fill_viridis(discrete=TRUE) 

ilum_map_final_v2 <- ilum_map_v2 + coord_map() 

print(ilum_map_final_v2)

csmontt

如今，使用该sf软件包来绘制所需的地图类型可能更容易。您可以在这里查看一些示例https://r-spatial.github.io/sf/articles/sf5.html

我从那里改编了一个示例，该示例显示了如何使用ggplot2其facet_wrap功能为给定变量的每个级别创建映射。

例如，如果您已经拥有一个具有一定数量级别的变量，则可能不需要此处显示的某些步骤。

library(sf)
library(ggplot2)
library(tidyr)
library(dplyr)
library(classInt)
library(viridis)

# Read example shapefile from sf package
nc <- st_read(system.file("shape/nc.shp", package="sf"))

# subset columns of interest as well as geometry column
# create BIR in which the variables BIR74, BIR79, NWBIR79
# become different levels of it
nc2 <- nc %>% select(BIR74, BIR79, NWBIR79, geometry) %>% gather(VAR, BIR, -geometry)

# HEre i just wanted to create 5 categories for the BIR variable
ints <- classIntervals(nc2$BIR, n = 5, style = "jenks")
nc2 <- nc2 %>% mutate(BIR_cat = cut(BIR, ints$brks, dig.lab=10)) 

# I just changed the levels's labels to match the output you are looking for
nc2 <- nc2 %>% mutate(values = ifelse(BIR_cat == "(3,1946]", "1", 
                                ifelse(BIR_cat == "(1946,4706]", "2", 
                                 ifelse(BIR_cat == "(4706,9087]", "3",
                                  ifelse(BIR_cat == "(9087,16184]", "4",
                                    ifelse(BIR_cat == "(16184,30757]", "5", NA))))))

# Map the spatial data
ggplot() +
 geom_sf(data = nc2, aes(fill = values)) +
 facet_wrap(~VAR, ncol = 1) +
 scale_fill_viridis(discrete=TRUE)