主页 / coding / 问题 / 78946558
Accepted
bill999
Asked: 2024-09-04 09:56:08 +0800 CST

如何在与州界图相同的坐标系上获取经纬度坐标

  • 772

我有一些坐标，例如：

library(tidyverse)
library(haven)
library(tidycensus)
library(tigris)

coords <- data.frame(lat = c(38.09720, 36.85298, 31.31517, 21.48344), long = c(-121.38785, -75.97742, -85.85522, -158.03648))

然后我得到一张美国地图：

geo <- get_acs(geography = "state",
               variables = c(x = "B04006_036"),
               year = 2021, 
               geometry = TRUE, 
               keep_geo_vars=TRUE) %>%
    filter(STATEFP!="72")

#to get alaska and hawaii in the picture
geo <- shift_geometry(geo)

然后我尝试绘制状态图，并叠加坐标：

ggplot(data = coords) +
    geom_point(aes(x=lat, y=long)) +
    geom_sf(fill = "transparent", color = "gray50", size = 1, data = geo %>% group_by(STATEFP) %>% summarise()) +   
    theme(panel.background = element_rect(fill = 'white')) +
    theme(panel.grid = element_blank(),axis.title = element_blank(),
          axis.text = element_blank(),axis.ticks = element_blank(),
          panel.border = element_blank())

得出的结果为：

在此处输入图片描述

但是，这不起作用，因为它生成的地图上所有坐标似乎都位于同一位置。我该如何修改以使地图和坐标处于同一比例？

1 个回答

  1. Best Answer

    这只是一个投影错误！您需要告诉 R（更具体地说是 sf）您的坐标位于哪个坐标参考系中。我假设它们位于典型的 WGS 1984（EPSG：4326）中。然后我们可以从您的coordsdf 创建一个 sf 对象并使用 geom_sf 进行绘图。

    library(tidyverse)
library(haven)
library(tidycensus)
library(tigris)
library(sf)

coords <- data.frame(lat = c(38.09720, 36.85298, 31.31517, 21.48344), long = c(-121.38785, -75.97742, -85.85522, -158.03648)) |>
  st_as_sf(coords = c("long", "lat"), crs = 4326) %>% # specify coordinate columns and coordinate reference system
  shift_geometry() # remember to shift the coords too!

geo <- get_acs(geography = "state",
               variables = c(x = "B04006_036"),
               year = 2021, 
               geometry = TRUE, 
               keep_geo_vars=TRUE) %>%
    filter(STATEFP!="72")

geo <- shift_geometry(geo)

ggplot() +
    geom_sf(data = coords) + # now you can use geom_sf
    geom_sf(fill = "transparent", color = "gray50", size = 1, data = geo %>% group_by(STATEFP) %>% summarise()) +   
    theme(panel.background = element_rect(fill = 'white')) +
    theme(panel.grid = element_blank(),axis.title = element_blank(),
          axis.text = element_blank(),axis.ticks = element_blank(),
          panel.border = element_blank())

    正确的情节

    • 1

相关问题