This was crossposted (and solved) on Stack Overflow:
I reply also here for completeness.
The problem seems related to the fact that ms_simplify()
adds names to the geometry column:
polys_sf<-st_read(system.file("shape/nc.shp", package="sf") ) %>%
st_transform(crs="+init=epsg:4326") %>%
ms_simplify(.)
names(st_geometry(polys_sf))
[1] "0" "1" "2" "3" "4" "5" "6" "7" "8" "9" "10" "11" "12" "13" "14" "15" "16" "17" "18" "19" "20" "21" "22" "23" "24" "25"
[27] "26" "27" "28" "29" "30" "31" "32" "33" "34" "35" "36" "37" "38" "39" "40" "41" "42" "43" "44" "45" "46" "47" "48" "49" "50" "51"
[53] "52" "53" "54" "55" "56" "57" "58" "59" "60" "61" "62" "63" "64" "65" "66" "67" "68" "69" "70" "71" "72" "73" "74" "75" "76" "77"
[79] "78" "79" "80" "81" "82" "83" "84" "85" "86" "87" "88" "89" "90" "91" "92" "93" "94" "95" "96" "97" "98" "99"
as suggested in Polygons and polylines do not display in Leaflet · Issue #880 · r-spatial/sf · GitHub, removing the names will solve the issue. Therefore, this works:
library(shiny)
library(shinydashboard)
library(leaflet)
library(sf)
library(rmapshaper)
### Read in shapefiles ###
polys_sf<-st_read(system.file("shape/nc.shp", package="sf") ) %>%
st_transform(crs="+init=epsg:4326") %>%
ms_simplify(.)
names(st_geometry(polys_sf)) = NULL
ui<- dashboardPage(
header = dashboardHeader(),
sidebar = dashboardSidebar(),
body = dashboardBody(
box(width=12,leafletOutput("leaf"))))
### Server ###
server<- function(input,output,session){
### This creates interactive map ###
output$leaf<- renderLeaflet({
leaflet(options = leafletOptions(minZoom = 7))%>%
addPolygons(data= polys_sf)
})
}
shinyApp(ui,server)
, while if the names(st_geometry(polys_sf)) = NULL
line is removed the polygons are not shown.
@KWANGER : please have a look at FAQ: Is it OK if I cross-post? regarding policies about cross-posting on this forum.