r-手动创建传单地图的点

Question

我正在创建几个点来绘制传单-R地图。然而，当试图用addCircles绘制点时，我得到了错误：

Warning: Error in derivePoints: Point data not found; please provide addCircles with data and/or lng/lat arguments

关于空间数据帧的信息如下：

Simple feature collection with 3 features and 4 fields
geometry type:  POINT
dimension:      XY
bbox:           xmin: -79.48837 ymin: 43.66537 xmax: -79.29187 ymax: 43.71345
epsg (SRID):    4326
proj4string:    +proj=longlat +datum=WGS84 +no_defs

我有另一个可用的空间数据帧，除了+datum=WGS84被+ellps=WGS84。会是这样吗？如果是，我该如何进行更改？

样本代码

library(shiny)
library(leaflet)
ui <- fluidPage(
leafletOutput("mymap")
)
server <- function(input, output, session) {
# Create tree geometries
tree_1g <- st_point(c(-79.2918671415814, 43.6760766531298))
tree_2g <- st_point(c(-79.4883669334101, 43.6653747165064))
tree_3g <- st_point(c(-79.2964680812039, 43.7134458013647))
# Create sfc object with multiple sfg objects
points_sfc <- st_sfc(tree_1g, tree_2g, tree_3g, crs = 4326)
# Create tree attributes
data <- data.frame (
id = c(1, 2, 3),
address = c(10, 20, 30),
street = c("first", "second", "third"),
tname = c("oak", "elm", "birch")
)
tree_data <- st_sf(data, geometry = points_sfc)
output$mymap <- renderLeaflet({
leaflet() %>%
addProviderTiles(providers$Stamen.Watercolor) %>%
# Centre the map in the middle of Toronto
setView(lng = -79.384293, 
lat = 43.685, #43.653908, 
zoom = 11) %>% 
addCircles(tree_data)
})
}
shinyApp(ui, server)

Answer 1

解决方案

您需要指定data = tree_data，因为在addCircles()调用中，data参数是最后一个。

leaflet() %>%
addProviderTiles(providers$Stamen.Watercolor) %>%
setView(lng = -79.384293, 
lat = 43.685,
zoom = 11) %>% 
addCircles(data = tree_data)

---

说明

addCircles()调用中的第一个参数是map，它是通过%>%运算符传入的。第二个参数是lng，所以你在通话中所做的相当于

addCircles(lng = tree_data)

---

备选方案

另一种将数据发送到addCircles()函数的方法是通过leaflet()调用

leaflet(tree_data) %>%
addProviderTiles(providers$Stamen.Watercolor) %>%
setView(lng = -79.384293, 
lat = 43.685,
zoom = 11) %>% 
addCircles()