我想绘制一个具有多个点(也称为纬度和经度坐标组合)的世界地图。
我不想使用墨卡托,因此我重新投影世界地图的数据和我的坐标。
当世界的投影发生变化时,所有点都会突然放置在地图的中间(这是一种常见行为,当投影不对齐时,请参阅https://www.earthdatascience.org/courses/earth-analytics/spatial-data-r/intro-to-coordinate-reference-systems/ https://www.earthdatascience.org/courses/earth-analytics/spatial-data-r/intro-to-coordinate-reference-systems/).
将投影分配给点时我做错了什么?
My code:
library(ggplot2)
library(sf)
library(rnaturalearth)
# assign a projection, for example ...
crs <- 3035
# get data for the world map and assign the projection
world <- ne_countries(scale = "medium", returnclass = "sf")
world <- st_transform(world, crs = crs)
# create data frame with three points, convert it to a spatial object
# and assign the same projection
points <- data.frame(longitude = c(-105.2519, 10.7500, 2.9833),
latitude = c(40.0274, 59.9500, 39.6167))
points <- st_as_sf(points, coords = c("longitude", "latitude"), crs = crs)
# plot the data with ggplot2:
ggplot() +
geom_sf(data = world) +
geom_sf(data = points, color = "red")
结果:
然而,当我使用标准投影 WGS84 时,它确实有效,即crs = 4326
):