ggmap叠加LSOA shp文件报错：找不到lon对象的技术求助

我正在自学将城镇的ggmap地图与.shp文件叠加，划分出LSOA（下层超级输出区），目的是更清晰地向当地领导展示特定区域、街道名称和地标相关的LSOA内事件，提升沟通效率。

按教程步骤操作：

• 获取Google Maps API并使用qmap创建ggmap地图对象
• 读取LSOA shp文件
• 将两者整合到同一个ggplot绘图中，对齐经纬度美学参数

编写的代码：

londonmap <- qmap("London")

LSOA<- readOGR(".", "Lower_Layer_Super_Output_Areas_(December_2011)_Boundaries_Super_Generalised_Clipped_(BSC)_EW_V3")
 
mymap <- londonmap + geom_polygon(aes(x = lon, y = lat), data = LSOA)

运行后报错：

"Error in FUN(X[[i]], ...) : object 'lon' not found"

请问哪里出错了？是不是地图对象和shp文件的经纬度不匹配导致的？

编辑1：dput(londonmap)返回结果：

structure(list(data =         structure(list(lon =         c(-0.566352679492181, 
0.312553570507799,   -0.566352679492181, 0.312553570507799),     lat = c(51.2324435804282, 
51.2324435804282, 51.7794952698017,     51.7794952698017)), out.attrs = list(
    dim = c(lon = 2L, lat = 2L),     dimnames = list(lon =  c("lon=-0.5663527", 
    "lon= 0.3125536"), lat =  c("lat=51.23244", "lat=51.77950"
    ))), class = "data.frame",   row.names = c(NA, -4L)), layers = list(
    <environment>, <environment>,  <environment>), scales = <environment>, 
    mapping = structure(list(x =     ~lon, y = ~lat), class = "uneval"), 
    theme =   structure(list(axis.title =   structure(list(), class =  c("element_blank", 
    "element")), axis.text =     structure(list(), class = c("element_blank", 
"element")), axis.ticks.length = structure(0, unit = 1L, class = c("simpleUnit", 
"unit", "unit_v2")), panel.background = structure(list(), class = c("element_blank", 
"element")), panel.spacing = structure(0, unit = 3L, class = c("simpleUnit", 
"unit", "unit_v2")), panel.grid.major = structure(list(), class = c("element_blank", 
"element")), panel.grid.minor = structure(list(), class = c("element_blank", 
"element")), plot.margin = structure(c(0, 0, 0, 0), unit = 3L, class = c("simpleUnit", 
"unit", "unit_v2")), legend.position = "right"), complete = FALSE, validate = TRUE), 
coordinates = <environment>, facet = <environment>, plot_env = <environment>, 
labels = list(x = "lon", y = "lat", xmin = "xmin", xmax = "xmax", 
    ymin = "ymin", ymax = "ymax")), class = c("gg", "ggplot"
))

编辑2：dput(LSOA)输出内容过大，无法粘贴。

核心问题 #

你用readOGR读取的LSOA是SpatialPolygonsDataFrame对象，不是普通数据框，没有直接的lon和lat列。geom_polygon无法直接识别这类空间对象的坐标信息，所以报错找不到lon。

修复步骤 #

推荐两种处理方式，优先选择方法2（当前空间数据处理主流方案）：

方法1：用fortify转换为数据框（旧方法）

library(ggplot2)
library(rgdal)

londonmap <- qmap("London")
LSOA <- readOGR(".", "Lower_Layer_Super_Output_Areas_(December_2011)_Boundaries_Super_Generalised_Clipped_(BSC)_EW_V3")

# 将空间对象转换为ggplot兼容的数据框
LSOA_df <- fortify(LSOA)

# 叠加绘图，必须指定group参数保证多边形正确绘制
mymap <- londonmap + geom_polygon(data = LSOA_df, aes(x = long, y = lat, group = group), 
                                  fill = NA, color = "red", size = 0.5)
print(mymap)

方法2：用sf包读取shp（推荐，更简洁）

sf包是R空间数据处理的标准工具，与ggplot2兼容性更好：

library(ggplot2)
library(ggmap)
library(sf)

londonmap <- qmap("London")
# 用sf读取shp文件
LSOA_sf <- st_read(".", "Lower_Layer_Super_Output_Areas_(December_2011)_Boundaries_Super_Generalised_Clipped_(BSC)_EW_V3")

# 直接用geom_sf叠加，inherit.aes=FALSE避免映射冲突
mymap <- londonmap + geom_sf(data = LSOA_sf, fill = NA, color = "red", inherit.aes = FALSE)
print(mymap)

额外注意点 #

• 检查坐标参考系（CRS）：ggmap的地图使用WGS84（EPSG:4326），如果你的LSOA shp文件不是这个CRS，用st_transform(LSOA_sf, 4326)转换。
• 调整样式：可以修改fill、color、size参数，让LSOA边界更符合展示需求。

内容的提问来源于stack exchange，提问作者SOFaddict